Radiographic equipment

Abstract

A radiation imaging device (1) includes: a plurality of pixels (G) generating electric charges corresponding to the energy or number of particles of incident radiation; a plurality of signal processing units (45) connected to each of the plurality of pixels (G) and generating digital values ​​based on the electric charges provided by the pixels (G); and a circuit substrate (3) on which a radiation detector (2) including a plurality of pixels (G) and a plurality of signal processing units (45) is two-dimensionally arranged. The plurality of signal processing units (45) respectively include: a signal conversion unit (46) converting an analog value based on the electric charges into a digital value; and a clock signal generation unit (48) providing a clock signal for generating a digital value to the signal conversion unit (46).

Description

Technical Field

[0001] The present invention relates to a radiation imaging device. Background Art

[0002] A technology for detecting radiation has been developed. Applications of radiation detection technology in the medical field, industrial field, security field, and the like are expected. As a device for detecting radiation, there is a radiation imaging device that obtains a radiation image. The radiation imaging device outputs image data representing the state of incident radiation. In the generation of image data, for example, signal processing is performed to convert an analog signal into a digital signal. The signal processing is performed by providing a clock signal that drives an electronic circuit that performs a desired function. Patent Documents 1 and 2 disclose devices for detecting X-rays or radiation. Furthermore, Patent Documents 1 and 2 show that these devices operate according to a clock.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application No. 2020-507753;

[0006] Patent document 2: International Publication No. 2020 / 077217. Summary of the invention

[0007] Problem that the invention aims to solve

[0008] In the technical field of radiographic devices, it is desired to increase the effective pixel area. Enlarging the effective pixel area is accompanied by an increase in the number of pixels. If the number of pixels increases, there is a tendency for power consumption to increase.

[0009] An object of the present invention is to provide a radiographic apparatus capable of suppressing an increase in power consumption.

[0010] Means used to solve problems

[0011] A radiographic device according to one aspect of the present invention includes: a plurality of pixels that generate electric charges corresponding to the energy or number of particles of incident radiation; a plurality of signal processing units that are connected to each of the plurality of pixels and generate digital values ​​based on the electric charges provided by the pixels; and a circuit substrate that two-dimensionally arranges a radiation detector including the plurality of pixels and the plurality of signal processing units. The plurality of signal processing units respectively include: a signal conversion unit that converts an analog value based on the electric charges into a digital value; and a clock signal generation unit that provides a clock signal for generating the digital value to the signal conversion unit.

[0012] The radiographic device is provided with a signal processing unit for each pixel. Moreover, the signal processing unit includes a signal conversion unit and a clock signal generating unit, respectively. That is, the radiographic device is provided with a clock signal generating unit for each pixel. According to this configuration, it is possible to drive only the signal conversion unit corresponding to the pixel incident with radiation and not drive the signal conversion unit corresponding to the pixel not incident with radiation. Therefore, even if the number of pixels increases, the signal conversion unit that does not need to be operated will not be operated, so the increase in power consumption can be suppressed.

[0013] The clock signal generating unit can start supplying the clock signal to the signal converting unit by using the generation of charges caused by the incidence of radiation on the pixel as a trigger. According to this configuration, the signal converting unit can be operated every time radiation is incident.

[0014] The radiographic device of one aspect of the present invention may further include: a transmission signal generating unit that provides a transmission signal for outputting a digital value from the signal processing unit to the circuit board to each of the plurality of signal processing units; and a wiring unit that transmits the transmission signal to the signal processing unit. According to this configuration, the output operations of the plurality of signal processing units can be synchronized.

[0015] Effects of the Invention

[0016] According to the present invention, there is provided a radiographic apparatus capable of suppressing an increase in power consumption. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a perspective view showing the structure of the radiation imaging device according to the embodiment.

[0018] Figure 2 Yes Figure 1 The radiographic apparatus shown is exploded and viewed in a perspective view from a first viewing angle.

[0019] Figure 3 Yes Figure 1 The radiographic apparatus is shown exploded and in a perspective view from a second viewing angle.

[0020] Figure 4 Yes Figure 1 FIG. 1 is an enlarged view of a radiation detector included in the radiation imaging device.

[0021] Figure 5 Yes means Figure 4 1 is a block diagram showing the configuration of a signal processing unit included in the radiation imaging apparatus shown.

[0022] Figure 6 It is a diagram for explaining the operation of the radiation imaging device. DETAILED DESCRIPTION

[0023] Figure 1 The radiation imaging device 1 shown obtains a two-dimensional image based on radiation reaching from the inspection object. The radiation is, for example, gamma rays, X-rays, alpha rays, and beta rays. The radiation imaging device 1 has a plurality of radiation detectors 2 and a circuit board 3. The radiation detector 2 is mounted on the circuit main surface 3a of the circuit board 3. The radiation detector 2 outputs a pixel signal corresponding to the incident radiation. The radiation detector 2 includes a plurality of pixels G (refer to Figure 4 ), each pixel G outputs a pixel signal. The pixel signal is used in the image generation unit 4 to generate a radiographic image. The circuit substrate 3 receives the pixel signal output from the radiation detector 2. The circuit substrate 3 has a signal line for providing a control signal from the control unit 5 to the radiation detector 2. In addition, the circuit substrate 3 has a signal line for outputting the pixel signal to the image generation unit 4. In addition, the circuit substrate 3 may have a signal line for electrically connecting the radiation detectors 2.

[0024] like Figure 2 and Figure 3 As shown, the radiation detector 2 includes a charge generating unit 10 and a readout unit 20. The charge generating unit 10 and the readout unit 20 are in the shape of plates. The radiation detector 2 has a stacked structure. The charge generating unit 10 is arranged on the readout unit 20. The charge generating unit 10 is electrically connected to the readout unit 20. The charge generating unit 10 generates charges corresponding to incident radiation. The charge generating unit 10 outputs the charges to the readout unit 20. The readout unit 20 generates a pixel signal using the charges generated by the charge generating unit 10.

[0025] The charge generating section 10 includes a semiconductor detecting section 11 , a control electrode section 12 , and a charge output electrode 13 .

[0026] The semiconductor detection unit 11 generates electron-hole pairs (charge pairs) using the received X-rays. That is, the semiconductor detection unit 11 converts the received radiation into a current signal (charge signal) corresponding to its energy. The planar shape of the semiconductor detection unit 11 is rectangular. The size of the semiconductor detection unit 11 is, for example, about 9.6 mm×9.6 mm. The semiconductor detection unit 11 has a semiconductor incident surface 11a that receives radiation such as X-rays and a semiconductor output surface 11b that outputs charges. The signal based on the charge is provided to the readout unit 20 from the semiconductor output surface 11b. As the semiconductor detection unit 11, for example, a Cd(Zn)Te charge generator, a Si charge generator, a Ge charge generator, a GaAs charge generator, a GaN charge generator, and a TlBr charge generator can be used. In addition, as the semiconductor detection unit 11, a device having a scintillator and a photodetector can be used. The scintillator converts X-rays into light. The photodetector converts the light generated by the scintillator into charges.

[0027] The control electrode portion 12 is provided on the semiconductor incident surface 11a. The control electrode portion 12 covers the entire surface of the semiconductor incident surface 11a. When viewed from above, the planar shape of the control electrode portion 12 coincides with the planar shape of the semiconductor incident surface 11a. The control electrode portion 12 forms an electric field in the region where the semiconductor detection portion 11 is arranged. The electric field determines the direction in which the charges generated by the semiconductor detection portion 11 move. The control electrode portion 12 generates an electric field in such a way that the internal charges of the semiconductor detection portion 11 move toward the semiconductor output surface 11b.

[0028] A plurality of charge output electrodes 13 are provided on the semiconductor output surface 11b. The charge output electrode 13 may also be a bump. One charge output electrode 13 corresponds to one pixel G. Therefore, the region where the charge output electrode 13 is arranged is a pixel region. For example, in a case where n charge output electrodes 13 are arranged on the first side and m charge output electrodes 13 are arranged on the second side, the total number of charge output electrodes 13 is k (k=n×m). In this case, it can be said that the number of pixels of one radiation detector 2 is k. Furthermore, in a case where the radiation imaging device 1 has p radiation detectors 2, it can be said that the number of pixels of the radiation imaging device 1 is r (r=k×p).

[0029] The number of pixels of one radiation detector 2 is, for example, 96. Therefore, the number of charge output electrodes 13 is also 96. As described above, if the size of the semiconductor detection unit 11 is a square of about 9.6 mm×9.6 mm, the interval between the charge output electrodes 13 is 100 μm. Figure 2 In the figures, for the convenience of illustration, the number of charge output electrodes 13 is shown as less than 96.

[0030] The readout section 20 generates a pixel signal based on the charge generated by the semiconductor detection section 11. The pixel signal is a digital value. The readout section 20 outputs the pixel signal to the circuit board 3. The readout section 20 includes an intermediate substrate 30 and a lead-out substrate 40.

[0031] The intermediate substrate 30 guides the charge generated by the semiconductor detection unit 11 to the lead-out substrate 40. As will be described in detail later, the configuration of the charge output electrode 13 is different from the configuration of the first lead-out electrode 41. Therefore, the intermediate substrate 30 has the function of connecting electrodes arranged at different positions. This function is called pitch conversion. Therefore, the intermediate substrate 30 is a pitch conversion substrate. The intermediate substrate 30 converts the pitch of the charge output electrode 13 of the semiconductor detection unit 11 into the pitch of the first lead-out electrode 41 of the lead-out substrate 40.

[0032] The intermediate substrate 30 has an intermediate input surface 30 a and an intermediate output surface 30 b. The intermediate input surface 30 a faces the charge generating section 10 , and the intermediate output surface 30 b faces the lead-out substrate 40 .

[0033] The intermediate input surface 30a is opposite to the semiconductor output surface 11b of the semiconductor detection unit 11. An intermediate input region 30S which is rectangular when viewed from above is provided on the intermediate input surface 30a. The intermediate input region 30S is set on substantially the entire surface of the intermediate input surface 30a. For example, the intermediate input region 30S may be the entire surface of the intermediate input surface 30a. A plurality of first intermediate electrodes 31 are arranged in the intermediate input region 30S at equal intervals in a two-dimensional shape. The first intermediate electrodes 31 are electrically connected to the charge output electrodes 13 of the semiconductor detection unit 11. Therefore, the pitch of the first intermediate electrodes 31 adjacent to each other is the same as the pitch of the charge output electrodes 13. For example, if the pitch of the charge output electrodes 13 is 100 μm, the pitch of the first intermediate electrodes 31 is also 100 μm. On the intermediate input surface 30a, the intermediate input region 30S corresponds to the pixel region.

[0034] The intermediate output surface 30b is provided with an intermediate output region 30R which is rectangular in plan view. When viewed from above, the entire intermediate output region 30R overlaps with the intermediate input region 30S. That is, the area of ​​the intermediate output region 30R is smaller than that of the intermediate input region 30S. A plurality of second intermediate electrodes 32 (second electrodes) are arranged two-dimensionally in the intermediate output region 30R.

[0035] The first intermediate electrode 31 (see Figure 2 ) is arranged near the side surface of the intermediate substrate 30. On the other hand, the second intermediate electrode 32 (refer to Figure 3 ) is not arranged near the side surface of the intermediate substrate 30. The second intermediate electrode 32 arranged at the outermost periphery is away from the side surface of the intermediate substrate 30. The distance from the second intermediate electrode 32 to the side surface of the intermediate substrate 30 is greater than the distance from the first intermediate electrode 31 to the side surface of the intermediate substrate 30. For example, the distance from the second intermediate electrode 32 to the side surface of the intermediate substrate 30 is greater than the length of the plurality of second intermediate electrodes 32. This distance corresponds to the width of the lead-out output portion 40R described later. If the width of the lead-out output portion 40R is 200 μm, the distance from the second intermediate electrode 32 to the side surface of the intermediate substrate 30 is also approximately 200 μm.

[0036] like Figure 4As shown, one first intermediate electrode 31 is electrically connected to one second intermediate electrode 32. Therefore, the intermediate substrate 30 has a wiring 33 that connects the first intermediate electrode 31 and the second intermediate electrode 32. There is no particular limitation on the configuration of the wiring 33. For example, the wiring 33 may be a combination of a portion extending in the thickness direction of the intermediate substrate 30 and a portion extending in the direction of the surface of the intermediate substrate 30. In addition, the wiring 33 may extend in a straight line from the first intermediate electrode 31 to the second intermediate electrode 32. This wiring structure is called an oblique through hole. By using the oblique through hole, the distance of the wiring from the first intermediate electrode 31 to the second intermediate electrode 32, that is, the pitch conversion distance, can be shortened. As a result, the influence of parasitic capacitance can be reduced.

[0037] The number of the first intermediate electrodes 31 is the same as the number of the second intermediate electrodes 32. The pitch P32 of the adjacent second intermediate electrodes 32 is smaller than the pitch P31 of the adjacent first intermediate electrodes 31. If the pitch P31 of the first intermediate electrodes 31 is 100 μm, the pitch P32 of the second intermediate electrodes 32 can be 80 μm. It should be noted that in the present embodiment, the plurality of second intermediate electrodes 32 are arranged at equal intervals, but the pitch P32 of the second intermediate electrodes 32 is not limited to equal intervals.

[0038] Refer again Figure 2 and Figure 3 The lead-out substrate 40 receives the charge and generates a pixel signal corresponding to the received charge. The lead-out substrate 40 has a lead-out input surface 40a and a lead-out output surface 40b. The lead-out input surface 40a is opposite to the intermediate output surface 30b. The lead-out output surface 40b is opposite to the circuit substrate 3. In addition, the lead-out substrate 40 has a lead-out input section 40S, a lead-out output section 40R, and a plurality of signal processing sections 45 (see Figure 4 ).

[0039] The lead-in / out portion 40S is formed on the lead-in / out surface 40a. The lead-in / out portion 40S includes a plurality of first lead-out electrodes 41. The arrangement of the first lead-out electrodes 41 corresponds to the arrangement of the second intermediate electrodes 32. That is, the first lead-out electrodes 41 are opposite to the second intermediate electrodes 32. As a result, one first lead-out electrode 41 is electrically connected to one second intermediate electrode 32. Furthermore, the first lead-out electrode 41 receives electric charge from the second intermediate electrode 32.

[0040] The derivation output unit 40R functions as an input and output unit for signals between the radiation detector 2 and other components (control unit 5 and image generation unit 4). For example, the derivation output unit 40R receives a control signal from the control unit 5. In addition, the derivation output unit 40R outputs a digital value to the image generation unit 4. The derivation output unit 40R is formed to surround the derivation input unit 40S. For example, the width of the derivation output unit 40R is 200 μm. When viewed from above, the derivation output unit 40R has a frame shape.

[0041] The lead-out output portion 40R includes a plurality of second lead-out electrodes 42. For example, in the frame-shaped lead-out output portion 40R, 50 second lead-out electrodes 42 are arranged on one side. Therefore, 200 second lead-out electrodes 42 are arranged on the four sides constituting the lead-out output portion 40R. One second lead-out electrode 42 is connected to one signal processing unit 45. The second lead-out electrode 42 surrounds the lead-out input portion 40S. In other words, on the lead-out input surface 40a, a plurality of second lead-out electrodes 42 are arranged in a manner surrounding a plurality of first lead-out electrodes 41. The second lead-out electrode 42 is a through electrode. That is, the second lead-out electrode 42 reaches the lead-out output surface 40b from the lead-out input surface 40a. The second lead-out electrode 42 is electrically connected to the circuit substrate 3 through a bump provided on the lead-out output surface 40b.

[0042] like Figure 4 As shown, the signal processing unit 45 converts the charge into a pixel signal as a digital value. One signal processing unit 45 is connected to one first extraction electrode 41. That is, one signal processing unit 45 is connected to one pixel G. Therefore, the readout unit 20 includes a plurality of signal processing units 45. The signal processing unit 45 receives the charge from the extraction input unit 40S. The signal processing unit 45 outputs a digital value from the extraction output unit 40R. In more detail, the signal processing unit 45 converts the charge output from the charge generating unit 10 into an energy integration signal as a pixel signal. The energy integration signal includes at least information on the energy of the incident radiation.

[0043] like Figure 5 As shown in FIG. 1 , the signal processing unit 45 includes a signal conversion unit 46, a memory 47, and a clock signal generating unit 48. Since the signal processing unit 45 is connected to each pixel G, the number of the signal processing units 45 is the same as the number of the pixels G. Similarly, the number of the signal conversion units 46 is the same as the number of the pixels G, the number of the memories 47 is the same as the number of the pixels G, and the number of the clock signal generating units 48 is the same as the number of the pixels G. That is, one signal conversion unit 46, one memory 47, and one clock signal generating unit 48 are connected to one pixel G.

[0044] The signal conversion unit 46 is connected to the charge output electrode 13 of the charge generation unit 10 via the wiring 33 of the intermediate substrate 30. The signal conversion unit 46 receives the charge from the charge generation unit 10. The signal conversion unit 46 converts the charge The analog signal is discretized. The analog signal is expressed as a voltage. The voltage corresponds to the energy of the radiation or the number of particles incident on the corresponding pixel G of the charge generating unit 10. Therefore, the signal conversion unit 46 is an A / D converter that outputs a digital signal. For example, the resolution of the signal conversion unit 46 can be 10 bits.

[0045] The signal conversion unit 46 operates by the clock signal θ2 provided from the clock signal generation unit 48. When receiving the clock signal θ2, the signal conversion unit 46 performs an operation of transmitting an analog signal generated by the incidence of radiation from the pixel G, an operation of resetting the charge accumulated in the pixel G, and an operation of converting the transmitted analog signal into a digital signal. It should be noted that the signal conversion unit 46 may perform other desired operations in addition to the above-mentioned operations.

[0046] The clock signal generating unit 48 generates a clock signal θ2 required for the operation of the signal conversion unit 46. Moreover, the clock signal generating unit 48 provides the clock signal θ2 to the signal conversion unit 46. That is, one clock signal generating unit 48 is connected to one signal conversion unit 46. In other words, the output destination of a certain clock signal generating unit 48 is a specific signal conversion unit 46. The signal conversion unit 46 is provided for each pixel G. Therefore, it can be said that the clock signal generating unit 48 is also provided for each pixel G. According to this configuration, the clock signal generating unit 48 can be configured in a manner adjacent to the signal conversion unit 46. As a result, the length of the signal line from the clock signal generating unit 48 to the signal conversion unit 46 can be shortened. When the signal line is shortened, the transmission distance of the clock signal θ2 is also shortened, and therefore, signal delay is less likely to occur. Furthermore, the frequency of the clock signal can also be increased to about 100 MHz.

[0047] The clock signal generating unit 48 causes radiation to enter the corresponding pixel G (see Figure 6 The clock signal generating unit 48 outputs a predetermined number of pulses according to the trigger. The number of pulses outputted may be the number required for the analog-to-digital conversion operation in the signal conversion unit 46. For example, when the incidence of radiation is detected once, the clock signal generating unit 48 outputs 16 pulses as the clock signal θ2.

[0048] Since the clock signal generating unit 48 is provided for each pixel G, the actions related to each pixel G can be independent. In other words, the actions of the plurality of signal conversion units 46 do not need to be synchronized. Therefore, a signal for synchronizing the actions of the plurality of signal conversion units 46 is also not required. For example, when radiation is incident on a certain pixel G, the signal conversion unit 46 can immediately start the action of generating a digital signal. That is, it can be said that the action of the signal conversion unit 46 is synchronized with the incidence of radiation. According to this action, the signal conversion process is performed immediately after the radiation is incident, so there will be no problem of phase shift. In addition, there will be no wasted waiting time. This action has a high affinity with respect to a photon counting type detector that performs signal conversion processing for each randomly incident particle.

[0049] Furthermore, at a certain time, when radiation is incident on a plurality of pixels G, the action of generating digital signals can be started independently. Furthermore, it is also possible to operate only the signal conversion unit 46 corresponding to the pixel G that generates the incident radiation, and not operate the signal conversion unit 46 corresponding to the pixel G that does not generate the incident radiation. In the case where the signal conversion action is performed uniformly on all pixels G, when the number of pixels increases, the power consumption also increases in proportion to the number of pixels. However, the radiation imaging device 1 of this embodiment can operate only the required signal conversion unit 46, so the power consumption is not proportional to the number of pixels. Therefore, it is possible to take into account both the suppression of the increase in the number of pixels and the increase in power consumption.

[0050] The memory 47 is connected to the signal conversion unit 46. The memory 47 receives the digital signal from the signal conversion unit 46. Furthermore, the memory 47 receives a digital signal each time. When saving the digital signal The memory 47 stores the digital signal The signals are stored in a predetermined memory space one by one. The memory 47 is connected to the control unit 5 via a wiring 51 (wiring unit). The input of the wiring 51 is one, and the output of the wiring 51 is multiple. Moreover, the input of the wiring 51 is connected to the control unit 5, and the output of the wiring 51 is connected to the memory 47 of the signal processing unit 45. That is, the transmission signal θ1 is output from one control unit 5 to multiple memories 47. The control unit 5 that outputs the transmission signal θ1 has a function as a transmission signal generating unit.

[0051] The memory 47 outputs a digital signal to the image generating unit 4 according to the transmission signal θ1 supplied from the control unit 5. That is, the memory 47 does not receive the clock signal θ2 and is therefore not controlled by the clock signal θ2. In other words, the operation of the signal conversion unit 46 and the operation of the memory 47 are based on different signals. Therefore, the respective operations are also independent of each other.

[0052] The radiographic device 1 includes: a plurality of pixels G that generate charges corresponding to the energy or number of particles of incident radiation; a plurality of signal processing units 45 that are connected to each of the plurality of pixels G and generate digital values ​​based on the charges provided by the pixels G; and a circuit substrate 3 that two-dimensionally arranges the radiation detector 2 including the plurality of pixels G and the plurality of signal processing units 45. The plurality of signal processing units 45 each include: a signal conversion unit 46 that converts an analog value based on the charges into a digital value; and a clock signal generation unit 48 that supplies a clock signal for generating a digital value to the signal conversion unit.

[0053] The radiographic device 1 is provided with a signal processing unit 45 for each pixel G. Furthermore, the signal processing unit 45 includes a signal conversion unit 46 and a clock signal generating unit 48. That is, the radiographic device 1 is provided with a clock signal generating unit 48 for each pixel G. According to this configuration, it is possible to drive only the signal conversion unit 46 corresponding to the pixel G incident with radiation, and not drive the signal conversion unit 46 corresponding to the pixel G not incident with radiation. Therefore, even if the number of pixels G increases, the signal conversion unit 46 that does not need to be operated will not be operated, so that the increase in power consumption can be suppressed.

[0054] The radiographic imaging device 1 of the present invention is not limited to the above-described embodiment.

[0055] Description of Reference Numerals

[0056] 1 radiation imaging device; 2 radiation detector; 3 circuit substrate; 4 image generating unit; 5 control unit; 10 charge generating unit; 20 readout unit; 11 semiconductor detecting unit; 12 control electrode unit; 13 charge output electrode; 11a semiconductor incident surface; 11b semiconductor output surface; 30 intermediate substrate; 40 lead-out substrate; 30a intermediate input surface; 30b intermediate output surface; 30S intermediate input region; 31 first intermediate electrode; 30R intermediate output region; 32 second intermediate electrode; 40a lead-out input surface; 40b lead-out output surface; 41 first lead-out electrode; 42 second lead-out electrode; 45 signal processing unit; 46 signal conversion unit; 47 memory; 48 clock signal generating unit.

Claims

1. A radiographic imaging device, wherein: have: A plurality of pixels generate electric charges corresponding to the energy of incident radiation or the number of particles; a plurality of signal processing sections connected to each of the plurality of pixels and generating digital values ​​based on the charge provided by the pixels; as well as A circuit board is provided with a radiation detector including a plurality of the pixels and a plurality of the signal processing units arranged two-dimensionally. Each of the plurality of signal processing units comprises: a signal conversion unit that converts an analog value based on the charge into the digital value; as well as The clock signal generating unit supplies the clock signal for generating the digital value to the signal converting unit.

2. The radiation imaging device according to claim 1, wherein: The clock signal generating section starts supplying the clock signal to the signal converting section using generation of the charge caused by the incidence of the radiation on the pixel as a trigger.

3. The radiation imaging device according to claim 1 or 2, wherein: Also features: a transmission signal generating section that provides a transmission signal for outputting the digital value from the signal processing section to the circuit substrate to each of the plurality of signal processing sections; as well as The wiring unit transmits the transmission signal to the signal processing unit.

Images