Radiography equipment

Abstract

To reduce the impact of noise due to an internal current upon a sensor module that detects a radiation image.SOLUTION: A radiographic device 100A comprises: a sensor module 3 provided with a plurality of radiation detection elements for detecting a radiation image which are arrayed in two-dimensional form; an electronic circuit board 6 on which is mounted a control circuit to control each part including the sensor module and generate a radiation image; a plurality of batteries 7A, 7B as power supplies; and electric conductors 8, 9 for connecting the plurality of batteries individually to the electronic circuit board. The electric conductors have a first section part 11 in which currents flow in mutually opposite directions on the same line parallel to signal wires 10 of the sensor module. Furthermore, the plurality of batteries have internal conduction parts 7A1 and 7B1 (7A2 and 7B2) in which currents flow in mutually opposite directions on the same line parallel to the signal wires of the sensor module.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a radiographic apparatus. [Background technology]

[0002] Radiography devices have many factors that cause current fluctuations, such as image reading and wireless transfer, which generate electromagnetic field noise from the internal electronic circuit boards, wiring between boards, and batteries. This electromagnetic field noise propagates to the TFT (thin film transistor) sensor module that detects radiation and is superimposed as noise on the image signal of the radiation image, causing noise such as horizontal streaks in the obtained radiation image, which can significantly reduce image quality. Therefore, one of the generally known means for reducing the electromagnetic field noise generated from the internal electronic circuit board is to place a metal shield between the electronic circuit board and the TFT sensor module (Patent Document 1, etc.). On the other hand, because the noise reduction effect of a shield is determined by (shield area) x (shield thickness), increasing the (shield thickness) will result in a greater noise reduction effect, but the weight of the shield will increase, which will reduce the value of a radiographic imaging device known as a flat panel detector (FPD), for which portability is one of its value propositions.

[0003] In the invention described in Patent Document 2, the wiring is placed close to or in contact with each other, and the magnetic fields generated in each wiring are caused to cancel each other out, thereby weakening the generated magnetic field or eliminating the magnetic field, thereby reducing the electromagnetic field noise in the TFT sensor module. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 05743477 [Patent Document 2] Patent No. 5811584 Summary of the Invention [Problem to be solved by the invention]

[0005] On the other hand, the inventors have discovered that the influence of electromagnetic field noise on the signal line of the TFT sensor module caused by a current flowing parallel to the signal line is more significant than that caused by a current flowing perpendicular to the signal line of the TFT sensor module.

[0006] An object of the present invention is to reduce the effect of noise due to an internal current on a sensor module that detects a radiation image, thereby reducing noise in a signal output by the sensor module. [Means for solving the problem]

[0007] One aspect of the radiographic imaging device of the present invention for solving the above problem comprises a sensor module having a plurality of radiation detection elements arranged in a two-dimensional shape for detecting a radiographic image, an electronic circuit board on which a control circuit is mounted for controlling each part including the sensor module and generating a radiographic image, a plurality of batteries as a power source, and electrical conductors individually connecting the plurality of batteries to the electronic circuit board, the electrical conductors having a first section portion through which currents flow in opposite directions to each other on the same line parallel to a signal line of the sensor module.

[0008] Another aspect of the radiographic imaging device according to the present invention comprises a sensor module having a plurality of radiation detection elements arranged in a two-dimensional shape for detecting a radiographic image, an electronic circuit board on which a control circuit is mounted for controlling each part including the sensor module and generating a radiographic image, a plurality of batteries as a power source, and electrical conductors individually connecting the plurality of batteries to the electronic circuit board, the plurality of batteries having internal conductive parts through which currents flow in opposite directions to each other on the same line parallel to the signal line of the sensor module. Effect of the Invention

[0009] According to the present invention, by reducing the effect of noise due to an internal current on a sensor module that detects a radiation image, it is possible to reduce noise in a signal output by the sensor module. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is a schematic cross-sectional view of an example of a radiation imaging apparatus. [Diagram 2] 1 is a rear view (interior see-through) of a radiation imaging apparatus according to an arrangement of a first embodiment of the present invention. [Diagram 3] FIG. 13 is a rear view (interior perspective) of a radiation imaging apparatus according to a comparative example. [Figure 4] FIG. 2 is a perspective view of a signal line and a power supply conductor for explaining the principle of canceling electromagnetic effects. [Diagram 5] 11 is a graph showing the level of electromagnetic field noise on each signal line. [Figure 6] FIG. 13 is a rear view (see-through inside) of a radiation imaging apparatus according to the arrangement of the second embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] 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 following embodiments and drawings.

[0012] As shown in FIG. 1, a radiographic imaging apparatus 100 according to one embodiment of the present invention comprises a housing including a front panel 1 and a back panel 2, a TFT sensor module 3, a lead sheet 4, a base 5, an electronic circuit board 6, a battery 7 as a power source, electrical conductors 8 and 9, etc. From the front panel 1 side, a TFT sensor module 3, a lead sheet 4, and a base 5 are stacked in this order, and an electronic circuit board 6 and a battery 7 are mounted on the rear surface of the base 5 facing the back panel 2.

[0013] The TFT sensor module 3 comprises a plurality of radiation detection elements arranged two-dimensionally to detect radiation images. The radiation detection elements are semiconductor elements such as photodiodes and phototransistors. The radiation detection elements generate electric charges according to the amount of radiation they are exposed to. Switching elements made of TFTs are connected one-to-one to the radiation detection elements and arranged two-dimensionally. By controlling the on / off timing of these switching elements, the detection analog signals of the radiation detection elements in each column are sent out through signal lines. The electronic circuit board 6 operates on power supplied from a battery 7, and is equipped with a control circuit that controls each part including the TFT sensor module 3 to generate a radiation image, as well as a power supply circuit and a communication circuit. The above points are related to the prior art. Fluctuating currents caused by the operation of the radiation imaging apparatus 100 can generate electromagnetic fields from the electronic circuit board 6, the electrical leads 8 and 9, and the battery 7, which can cause noise in the TFT sensor module 3.

[0014] First embodiment Fig. 2 shows a radiation imaging apparatus 100A according to the arrangement of the first embodiment of the present invention. Fig. 3 shows a radiation imaging apparatus 100Z according to the arrangement of a comparative example. The cross-sectional configuration shown in Fig. 1 is the same.

[0015] 2 is an internal perspective view seen from the back panel 2 side, showing an electronic circuit board 6, two batteries 7A and 7B, and electrical conductors 8 and 9. Also shown behind are signal lines 10 of the TFT sensor module 3. The signal lines 10 run parallel to each other in one direction (vertical direction). Battery 7A is connected to electronic circuit board 6 by electrical conductor 8, and battery 7B is connected to electronic circuit board 6 by electrical conductor 9, respectively. The wiring connecting the positive electrode of battery 7A to electronic circuit board 6 is designated as electrical conductors 8P1 and 8P2. The wiring connecting the negative electrode of battery 7A to electronic circuit board 6 is designated as electrical conductors 8N1 and 8N2. The wiring connecting the positive electrode of battery 7B to electronic circuit board 6 is designated as electrical conductors 9P1 and 9P2. The wiring connecting the negative electrode of battery 7B to electronic circuit board 6 is designated as electrical conductors 9N1 and 9N2.

[0016] The electric conductor 8P1 and the electric conductor 9P1 according to this embodiment correspond to a first section 11 in which currents flow in the opposite directions on the same line parallel to the signal line 10 of the TFT sensor module 3. The electric conductor 8N1 and the electric conductor 9N1 according to this embodiment correspond to a first section 11 in which currents flow in the opposite directions on the same line parallel to the signal line 10 of the TFT sensor module 3. The first section 11 is configured so that the amount of magnetic field generated by a current flowing in one direction is the same as the amount of magnetic field generated by a current flowing in the opposite direction. For this reason, in the embodiment shown in Fig. 2, the multiple batteries mounted are two batteries 7A, 7B of the same specifications, and a portion 8P1 (8N1) belonging to the first section 11 of the electric conductor 8 connected to one battery 7A and a portion 9P1 (9N1) belonging to the first section 11 of the electric conductor 9 connected to the other battery 7B have the same length and cross-sectional area.

[0017] 2, when the two-dimensional array of multiple radiation detection elements is viewed in a plan view, the electrical conductors 8 and 9 have a second section 12 that is perpendicular to the signal line 10 of the TFT sensor module 3. The electrical conductors 8P2, 8N2, 9P2, and 9N2 belong to the second section 12. The second section 12 is longer than the first section 11. Specifically, the electrical conductor 8P2 is longer than the electrical conductor 8P1, the electrical conductor 8N2 is longer than the electrical conductor 8N1, the electrical conductor 9P2 is longer than the electrical conductor 9P1, and the electrical conductor 9N2 is longer than the electrical conductor 9N1.

[0018] Furthermore, the multiple batteries 7A, 7B according to this embodiment have internal conductive parts 7A1 and 7B1, and internal conductive parts 7A2 and 7B2, through which currents flow in opposite directions on the same line parallel to the signal line 10 of the TFT sensor module 3. The internal conductive parts 7A1 and 7B1 form a pair through which currents flow in opposite directions on the same line parallel to the signal line 10. Similarly, the internal conductive parts 7A2 and 7B2 form a pair through which currents flow in opposite directions on the same line parallel to the signal line 10. In the embodiment shown in Figure 2, the multiple batteries 7A, 7B are arranged upside down so that the positive electrodes face each other and the negative electrodes face each other in a direction parallel to the signal line 10, and the batteries have internal conductive parts 7A1 and 7B1, and internal conductive parts 7A2 and 7B2, through which currents flow in opposite directions on the same line parallel to the signal line 10 of the TFT sensor module 3. The current flowing in the batteries 7A and 7B flows from the negative electrode to the positive electrode over the entire surface of the battery, and the amount of current is larger the closer to the electrode.

[0019] Although noise can be superimposed on the signal line 10 due to the influence of a magnetic field generated by the current flowing through the electrical conductors 8 and 9, the influence of the current running parallel to the signal line 10 is relatively large, and the influence of the current perpendicular to the signal line 10 is relatively small. The second section 12 is longer than the first section 11, but is disposed perpendicular to the signal line 10, so that the influence of noise from the second section 12 on the signal can be kept low.

[0020] In the radiation imaging apparatus 100A of this embodiment, the influence of the current running parallel to the signal line 10 on the signal is offset by the following effects. That is, the effect on the signal line 10 of the current flowing through the electric conductor 8P1 and the effect on the signal line 10 of the current flowing through the electric conductor 9P1 are the same in magnitude but opposite in polarity, so they cancel each other out and the effect on the signal is suppressed. This cancellation principle will be explained with reference to FIG. 4. As shown in FIG. 4, the magnetic field generated by the electric conductor 8P1 and the magnetic field generated by the electric conductor 9P1 are in opposite directions. The signal flowing through the signal line 10i is affected by the magnetic field generated by the electric conductor 8P1 in the vicinity of the electric conductor 8P1, but is affected by the magnetic field generated by the electric conductor 9P1 in the vicinity of the electric conductor 9P1 with almost the same amount and opposite polarity, so the two are canceled out. That is, by applying electromagnetic field noise of the same magnitude but opposite direction to the same signal line 10i, the noise effect is canceled out. Due to a similar cancellation principle, the effect of the current flowing through electrical conductor 8N1 on signal line 10j and the effect of the current flowing through electrical conductor 9N1 on signal line 10j are the same magnitude but opposite polarity, so they cancel each other out and the effect on the signal is reduced.

[0021] Furthermore, due to a similar cancellation principle, the effect of the current flowing through the internal conductive portion 7A1 on the signal line 10j and the effect of the current flowing through the internal conductive portion 7B1 on the signal line 10j are cancelled out, and the effect of the current flowing through the internal conductive portion 7A2 on the signal line 10i and the effect of the current flowing through the internal conductive portion 7B2 on the signal line 10i are cancelled out, thereby suppressing the effects on the signal.

[0022] As described above, according to the radiation imaging apparatus 100A of the present embodiment, the noise effect on the TFT sensor module 3 of the magnetic field generated by the internal current can be reduced, thereby reducing noise in the signal output by the TFT sensor module 3. In order to maximize the above-mentioned offsetting effect, the amount of magnetic field generated by the current flowing in one direction in the first section 11 is made equal to the amount of magnetic field generated by the current flowing in the opposite direction, as described above. Also, in the batteries 7A and 7B, the amount of magnetic field generated by the current flowing in one direction and the current flowing in the opposite direction with respect to the internal current flowing along the signal line 10 is made equal to the amount of magnetic field generated by the current flowing in the same direction.

[0023] In contrast, in the radiography apparatus 100Z according to the comparative example shown in FIG. 3, currents flow in the same direction in the electric conductors 8 and 9 and in the batteries 7A and 7B on the same line parallel to the signal line 10. Therefore, as shown by the solid line graph Z in FIG. 5, electromagnetic field noise is significantly increased. In FIG. 5, the vertical axis indicates the noise level, and the horizontal axis indicates the horizontal coordinate axis of the image, which is perpendicular to the signal line. In the radiography apparatus 100Z according to the comparative example shown in FIG. 3, the noise level included in the signal extracted from the signal lines 10i and 10j running parallel to the power supply current has a high peak as shown in FIG. 5. According to the radiography apparatus 100A according to the present embodiment shown in FIG. 2, the overall noise level including the signal extracted from the signal lines 10i and 10j is suppressed to a low level as shown by the dashed line graph A in FIG. 5.

[0024] Second Embodiment Next, a second embodiment of the present invention in which the number of mounted batteries is three will be disclosed. 6 shows a radiation imaging apparatus 100B according to a second embodiment of the present invention. The cross-sectional configuration shown in FIG. The radiation imaging apparatus 100B of this embodiment is equipped with three batteries 7C, 7D, and 7E. For simplicity, only the positive electrode wiring is shown as an electrical conductor. As shown in FIG. 6, the positive wiring from the three batteries 7C, 7D, and 7E is defined as electrical conductor 21P, electrical conductor 22P, and electrical conductor 23P, and each section is defined as electrical conductor 21P1, 21P2, and 21P3, electrical conductor 22P1, 22P2, and 22P3, and electrical conductor 23P1, 23P2, and 23P3.

[0025] The electrical conductor 21P2, the electrical conductor 22P2, and the electrical conductor 23P2 belong to the first section 11. Note that the electrical conductor 22P2 is disposed on the same line as the electrical conductor 21P2 and the electrical conductor 23P2, but is drawn shifted from them in the drawing. The effect of the current flowing through electrical conductor 21P2 on signal line 10k and the effect of the current flowing through electrical conductors 22P2 and 23P2 on signal line 10k are the same in magnitude but opposite in polarity, so they cancel each other out and the effect on the signal is suppressed. In order to maximize this offsetting effect, the amount of current flowing from each of the batteries 7C, 7D, and 7E is adjusted. Therefore, by changing the thickness of each of the electric conductors 21P, 22P, 23P and the length to the electronic circuit board 6, the impedance of the wiring is changed and the amount of current flowing through each of the electric conductors 21P, 22P, 23P is adjusted. Furthermore, among the electrical conductors 21P2, 22P2, and 23P2, the longer the section that runs parallel to the signal line 10, the greater the magnetic field influence on the signal line 10. Therefore, the degree of influence on the signal line 10 is adjusted by adjusting the length of the electrical conductor 21P2 connected to battery 7C and the lengths of the electrical conductors 22P2 and 23P2 connected to batteries 7D and 7E. As a result, the effect of the current flowing through the electrical conductor 21P2 on the signal line 10k (magnet field generation amount) and the effect of the current flowing through the electrical conductors 22P2 and 23P2 on the signal line 10k (magnet field generation amount) are adjusted to be equal in magnitude. As a result, the effects of both on the signal line 10k (magnet field generation amount) are the same in magnitude but opposite in polarity, so they cancel each other out and the effect on the signal is suppressed.

[0026] The electrical conductors 21P1 and 21P3, the electrical conductors 22P1 and 22P3, and the electrical conductors 23P1 and 23P3 belong to the second section 12. The second section 12 (21P1+21P3, 22P1+22P3, 23P1+23P3) is longer than the first section 11 (21P2, 22P2, 23P2), but is arranged perpendicular to the signal line 10, so that the effect of noise from the second section 12 on the signal can be kept low. Furthermore, the three batteries 7C, 7D, and 7E are also arranged so that their internal currents intersect at right angles with the signal line 10, so that the effect of noise on signals from the internal currents of the batteries 7C, 7D, and 7E can be kept low.

[0027] Although not shown in the figure, the negative wiring of batteries 7C, 7D, and 7E can also be arranged to have a first section and a second section, similar to the positive wiring, thereby reducing the effect of noise on signal line 10.

[0028] As described above, according to the radiation imaging apparatus 100B of the present embodiment, the noise effect on the TFT sensor module 3 of the magnetic field generated by the internal current can be reduced, thereby reducing noise in the signal output by the TFT sensor module 3. In order to maximize the above-mentioned offsetting effect in the radiation imaging apparatus 100B, the amount of magnetic field generated by a current flowing in one direction in the first section 11 is set to be equal to the amount of magnetic field generated by a current flowing in the opposite direction. According to the above embodiment, the magnetic fields generated from the battery and its wiring are not weakened by canceling each other out, but are allowed to affect the signal line 10 as they are, and the magnetic field effects of opposite directions are applied to the same signal line, thereby canceling out the effects on the signal line. According to the above embodiment, a sufficient noise reduction effect can be obtained without disposing a shield between the electronic circuit board 6, the battery 7, the electrical conductors 8 and 9, and the TFT sensor module 3, so that a lightweight structure can be achieved, and it is possible to provide users with a radiography device that does not compromise both image quality and portability. [Explanation of symbols]

[0029] 1 Front plate 2 Back plate 3 TFT Sensor Module 4 Lead Sheet 5 Base 6. Electronic Circuit Boards 7. Battery 7A, 7B battery 7A1 Internal conductive part 7A2 Internal conductive part 7B1 Internal conductive part 7B2 Internal conductive part 7C, 7D, 7E Batteries 8,9 Electrical conductors 10 Signal Line 11 First Section 12 Second section 21P, 22P, 23P Electrical conductor 100 Radiography equipment 100A Radiography apparatus (first embodiment) 100B Radiation imaging device (second embodiment) 100Z Radiography Device (Comparative Example)

Claims

1. a sensor module including a plurality of radiation detection elements arranged two-dimensionally for detecting a radiation image; an electronic circuit board on which a control circuit for controlling each unit including the sensor module and generating a radiation image is mounted; Multiple batteries as a power source; and electrical leads individually connecting the plurality of batteries to the electronic circuit board; The electrical conductor has a first section through which currents flow in opposite directions on the same line parallel to a signal line of the sensor module.

2. 2. The radiographic imaging apparatus according to claim 1, wherein the first section is configured so that an amount of a magnetic field generated by a current flowing in one direction is equal to an amount of a magnetic field generated by a current flowing in the opposite direction.

3. 2. The radiographic imaging device of claim 1, wherein the plurality of batteries are two batteries of the same specifications, and the portion belonging to the first section of the electrical conductor connected to one battery and the portion belonging to the first section of the electrical conductor connected to the other battery have the same length and cross-sectional area.

4. When the two-dimensional array of the plurality of radiation detection elements is viewed in a plan view, the electrical conductor has a second section that is perpendicular to a signal line of the sensor module, The radiation imaging apparatus according to claim 1 , wherein the second section is longer than the first section.

5. 5. The radiographic imaging apparatus according to claim 1, wherein the plurality of batteries have internal conductive parts through which currents flow in mutually opposite directions on the same line parallel to a signal line of the sensor module.

6. 6. The radiation imaging apparatus according to claim 5, wherein the plurality of batteries are arranged upside down so as to have internal conductive parts through which currents flow in opposite directions on the same line parallel to the signal line of the sensor module.

7. a sensor module including a plurality of radiation detection elements arranged two-dimensionally for detecting a radiation image; an electronic circuit board on which a control circuit for controlling each unit including the sensor module and generating a radiation image is mounted; Multiple batteries as a power source; and electrical leads individually connecting the plurality of batteries to the electronic circuit board; The plurality of batteries have internal conductive parts through which currents flow in mutually opposite directions on the same line parallel to a signal line of the sensor module.

8. 8. The radiation imaging apparatus according to claim 7, wherein the plurality of batteries are arranged upside down so as to have internal conductive parts through which currents flow in opposite directions on the same line parallel to the signal line of the sensor module.

Images