JP2007000249A - Imaging sensor and imaging device using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an imaging sensor capable of accurately reading electric charge information, and an imaging device using the same. <P>SOLUTION: Noise of the same amplitude enters a gate driver circuit 38 to drive to a flat panel X-ray detector (FPD) 3 by applying driving signals to the detector whenever the driving signals are switched on or off as a control circuit 5 controls the motion of a switching power supply 39 as synchronized with the driving signals from the circuit 38. If the noise has the same amplitude, the noise can be corrected by means of the offset correction and can be removed. Accordingly, even if the noise of the same amplitude enters, the carrier, which is the electric charge information, can be accurately read by correcting the noise by means of the offset correction, etc. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an image sensor used in the medical field, industrial field, and nuclear field, and an image pickup apparatus using the same.

  An imaging apparatus that performs imaging based on detected light or radiation includes a light or radiation detector that detects light or radiation. An X-ray detector will be described as an example. The X-ray detector has an X-ray sensitive X-ray conversion layer (semiconductor layer), and the X-ray conversion layer converts into carriers (charge information) by the incidence of X-rays, and reads the converted carriers. To detect X-rays. As the X-ray conversion layer, an amorphous selenium (a-Se) film is used (for example, see Non-Patent Document 1).

  When radiation imaging is performed by irradiating the subject with X-rays, a radiation image transmitted through the subject is projected onto the amorphous selenium film, and carriers proportional to the density of the image are generated in the film. After that, the carriers generated in the film are collected by the two-dimensionally arranged carrier collecting electrodes and integrated for a predetermined time (also referred to as “accumulation time”). Read out.

  Around such an X-ray detector, peripheral circuits such as a gate driver circuit for switching ON / OFF of switching of the thin film transistor and an amplifier array circuit for reading carriers are arranged. The drive circuit gives a drive signal to the X-ray detector to drive the X-ray detector, and the amplifier array circuit receives the read carrier based on a read signal related to reading of the carrier. These circuits and an X-ray detector constitute an image sensor.

By the way, when the power supply is a switching power supply, a technique has been proposed in which each drive signal is operated in a cycle that is an integral multiple of the reference clock in synchronization with the reference clock of the switching power supply (for example, see Patent Document 1).
Japanese Patent Laying-Open No. 2005-87254 (pages 10, 12-15, FIGS. 6 and 10) W. Zhao, et al., "A flat panel detector for digital radiology using active matrix readout of amorphous selenium," Proc. SPIE Vol. 2708, pp. 523-531, 1996.

  However, peripheral circuits such as gate driver circuits and amplifier array circuits are very sensitive to noise from the power supply. Therefore, power is supplied from the power supply by a dropper method that simply rectifies the voltage to a predetermined voltage. In the case of this dropper system, low noise can be realized, but the power source body becomes large. Further, there is a problem that self-heating is large and conversion efficiency is poor.

  On the other hand, in the case of a switching method that is small and has good conversion efficiency, as described in the above-mentioned problem of Patent Document 1, noise due to the switching operation is large. For example, when the power supply internal circuit is switched ON / OFF (switching operation) as shown in FIG. 8, a ripple voltage is generated as an AC component at the time of switching, and noise due to the ripple voltage is superimposed. If such a switching method is employed as it is, it will be impossible to accurately read out charge information (ie, carriers) due to the influence of each circuit due to noise. Although it is conceivable to remove noise by a filter, noise such as the ripple described above cannot be removed. Thus, although the above-described problem can be solved by the above-described Patent Document 1, it is desired that the problem be solved by a method other than Patent Document 1.

  The present invention has been made in view of such circumstances, and an object thereof is to provide an imaging sensor that can accurately read out charge information and an imaging apparatus using the imaging sensor.

In order to achieve such an object, the present invention has the following configuration.
That is, according to the first aspect of the present invention, light or radiation detection detects light or radiation by converting the light or radiation information into charge information by the incidence of light or radiation and reading the converted charge information. , Drive means for driving the detector by giving a drive signal, read means for receiving the read charge information based on a read signal related to reading of the charge information, the drive means and the read means An imaging sensor including a power supply for supplying power to at least one of the driving means, and in synchronization with at least one of the driving signal from the driving means and the reading signal to the reading means Control means for controlling the power supply to operate is provided.

  [Operation / Effect] According to the first aspect of the present invention, reading is performed based on the driving means for driving the light or radiation detector by supplying the driving signal and the reading signal related to the reading of the charge information. For the readout means that receives the charge information, the drive signal or the readout signal is turned on by performing control that the power supply operates in synchronization with at least one of the drive signal from the drive means and the readout signal to the readout means. Alternatively, noise with the same amplitude is input every time the switch is turned OFF. If the noise has the same amplitude, it can be corrected and removed by offset correction or the like. Therefore, even if noise with the same amplitude is mixed, the charge information can be accurately read out by correcting it by offset correction or the like.

  Also, during driving, the timing for sampling read data related to charge information (an example of a read signal) and the timing of A / D conversion for converting an analog value into a digital value (an example of a read signal) are most sensitive to noise. Become. Therefore, since it is not sensitive to noise at other timings, a low-noise imaging sensor can be realized if the power supply operates so as to synchronize with other timings. As a result, charge information can be read accurately.

  An example of the power supply of the invention described above is a switching power supply that generates a DC voltage (the invention according to claim 2). In the case of a switching power supply, it is possible to realize a downsized imaging sensor that is likely to contain large noise. By applying the present invention, it is possible to realize an image sensor with low noise and a reduced size.

  The invention according to claim 3 is an image pickup apparatus using the image pickup sensor according to claim 1 or 2, wherein the apparatus includes the image sensor and image processing means for performing image processing. The imaging sensor converts light or radiation information into charge information by the incidence of light or radiation, and detects light or radiation by reading the converted charge information; and At least one of driving means for driving the detector by supplying a driving signal, reading means for receiving the read charge information based on a read signal related to reading of the charge information, and the driving means and the reading means A power supply for supplying power to one means, and at least a drive signal from the drive means and a read signal to the read means Control means for controlling the power supply to operate in synchronization with one of the signals, and the image processing means performs image processing based on data detected by the light or radiation detector, and the detector The imaging is performed by a series of processes of detection and image processing by the image processing unit.

  [Operation / Effect] According to the third aspect of the present invention, reading is performed based on the driving means for driving the light or radiation detector by supplying the driving signal and the reading signal related to the reading of the charge information. For the readout means for receiving the charge information, the charge information is accurately read out by controlling the power supply to operate in synchronization with at least one of the drive signal from the drive means and the readout signal to the readout means. Can do. Therefore, the light or radiation detector can accurately detect data based on the accurately read charge information, and can accurately perform imaging by a series of image processing by the image processing means. .

  In the above-described invention, it is preferable to provide an offset correction means for performing offset correction on data detected by a light or radiation detector (the invention according to claim 4). If such an offset correction means is provided, when noise having the same amplitude is input every time the drive signal is switched ON or OFF, the noise can be corrected and removed by the offset correction means. Therefore, even if noise with the same amplitude is mixed, if it is corrected by offset correction, the charge information can be read accurately, and imaging can be accurately performed by a series of image processing by the image processing means.

  According to the imaging sensor and the imaging apparatus using the imaging sensor according to the present invention, the reading is performed based on the driving unit that drives the light or radiation detector by driving the driving signal and the readout signal related to the readout of the charge information. For the readout means that receives the charge information, the charge information is accurately read out by controlling the power supply to operate in synchronization with at least one of the drive signal from the drive means and the readout signal to the readout means. be able to.

Embodiment 1 of the present invention will be described below with reference to the drawings.
FIG. 1 is a block diagram of the X-ray fluoroscopic apparatus according to the first embodiment, and FIG. 2 is an equivalent circuit of a flat panel X-ray detector used in the X-ray fluoroscopic apparatus as viewed from the side. FIG. 3 is an equivalent circuit of the flat panel X-ray detector in plan view. In Example 1, including Example 2 described later, a flat panel X-ray detector (hereinafter referred to as “FPD” as appropriate) is taken as an example of a light or radiation detector, and X-ray fluoroscopic imaging is used as an imaging device. The apparatus will be described as an example.

  As shown in FIG. 1, the X-ray fluoroscopic apparatus according to the first embodiment including the second embodiment to be described later, and the top plate 1 on which the subject M is placed, and the X-ray toward the subject M are arranged. And an FPD 3 that detects X-rays transmitted through the subject M. The FPD 3 corresponds to the radiation detector in the present invention.

  In addition, the X-ray fluoroscopic apparatus includes a top panel control unit 4 that controls the elevation and horizontal movement of the top panel 1, a control circuit 5 that controls scanning of the FPD 3, and the tube voltage and tube current of the X-ray tube 2. An X-ray tube control unit 7 having a high voltage generation unit 6 to be generated, an A / D converter 8 that digitizes and extracts an X-ray detection signal that is a charge signal from the FPD 3, and an A / D converter 8 An image processing unit 9 that performs various processes based on the X-ray detection signal, a controller 10 that controls each of these components, a memory unit 11 that stores processed images, and an input that is input by an operator And a monitor 13 for displaying the processed image and the like.

  The top board control unit 4 horizontally moves the top board 1 to accommodate the subject M up to the imaging position, moves the top and bottom, rotates and horizontally moves the subject M to a desired position, or horizontally moves the subject M. Then, the image is picked up, or the image is moved horizontally after the image pickup is finished, and the control is performed to retract from the image pickup position. The control circuit 5 performs control related to scanning by horizontally moving the FPD 3 or rotating around the body axis of the subject M. The high voltage generation unit 6 generates a tube voltage and a tube current for irradiating X-rays and applies them to the X-ray tube 2. The X-ray tube control unit 7 moves the X-ray tube 2 horizontally, Control relating to scanning by rotating around the axis of the body axis of M, control of the setting of the irradiation field of the collimator (not shown) on the X-ray tube 3 side, and the like are performed. When scanning the X-ray tube 2 or the FPD 3, the X-ray tube 2 and the FPD 3 move while facing each other so that the FPD 3 can detect the X-rays emitted from the X-ray tube 2.

  The controller 10 is configured by a central processing unit (CPU) and the like, and the memory unit 11 is configured by a storage medium represented by ROM (Read-only Memory), RAM (Random-Access Memory), and the like. Yes. The input unit 12 includes a pointing device represented by a mouse, a keyboard, a joystick, a trackball, a touch panel, and the like. In the fluoroscopic imaging apparatus, the FPD 3 detects X-rays transmitted through the subject M, and the image processing unit 9 performs image processing based on the detected X-rays, thereby imaging the subject M. The image processing unit 9 corresponds to the image processing means in this invention.

  In the first embodiment, an offset correction unit 9 a is disposed between the A / D converter 8 and the image processing unit 9. The offset correction unit 9a performs offset correction on the digitized charge signal data detected by the FPD 3. In the first embodiment, a noise amplitude value, which will be described later, is set as an offset value that is a basis for offset correction. Therefore, noise can be removed by performing offset correction by subtracting the amplitude of the noise from the charge signal. The offset correction unit 9a corresponds to the offset correction means in this invention.

  In the first embodiment, the control circuit 5 has a function of controlling the switching power supply 39 to operate in synchronization with a drive signal from a gate driver circuit 38 described later. Specific functions of the control circuit 5 will be described later. The FPD 3 and the control circuit 5 constitute an image sensor (see the image sensor S in FIG. 3) in the present invention. The control circuit 5 corresponds to the control means in this invention.

  As shown in FIG. 2, the FPD 3 includes a radiation-sensitive semiconductor thick film 31 in which carriers are generated when radiation such as X-rays enters, and a voltage application electrode 32 provided on the surface of the semiconductor thick film 31. The carrier collecting electrode 33 provided on the back surface opposite to the radiation incident side of the semiconductor thick film 31, the charge storage capacitor Ca for collecting the collected carriers to the carrier collecting electrode 33, and the capacitor Ca. It includes a thin film transistor (TFT) Tr, which is a switch element for taking out charges that is normally OFF (blocked) for taking out charges. In Example 1, including Example 2 to be described later, the semiconductor thick film 31 is formed of a radiation-sensitive material, for example, amorphous selenium, in which carriers are generated by the incidence of radiation. May be a light-sensitive substance that produces

  In addition to this, the first embodiment including the second embodiment described later includes a data line 34 connected to the source of the thin film transistor Tr and a gate line 35 connected to the gate of the thin film transistor Tr. The voltage application electrode 32, the semiconductor thick film 31, the carrier collection electrode 33, the capacitor Ca, the thin film transistor Tr, the data line 34, and the gate line 35 are laminated on the insulating substrate 36.

  As shown in FIGS. 2 and 3, for each of the carrier collection electrodes 33 formed in a large number (for example, 1024 × 1024 or 4096 × 4096) in a vertical / horizontal two-dimensional matrix arrangement, The capacitor Ca and the thin film transistor Tr are connected to each other, and the carrier collecting electrode 33, the capacitor Ca, and the thin film transistor Tr are separately formed as each detection element DU. Further, the voltage application electrode 32 is formed over the entire surface as a common electrode of all the detection elements DU. Further, as shown in FIG. 3, the data lines 34 described above are arranged in parallel in the horizontal (X) direction, and the gate lines 35 described above are arranged in the vertical (Y) direction as shown in FIG. The data lines 34 and the gate lines 35 are connected to the detection elements DU. The data line 34 is connected to the amplifier array circuit 37, and the gate line 35 is connected to the gate driver circuit 38. The number of detector elements DU arranged is not limited to the above-mentioned 1024 × 1024 or 4096 × 4096, and the number of detector elements DU can be changed according to the embodiment. Therefore, the form with only one detection element DU may be sufficient.

  The detection elements DU are patterned on the insulating substrate 36 in a two-dimensional matrix arrangement, and the insulating substrate 36 on which the detection elements DU are patterned is also called an “active matrix substrate”.

  When the periphery of the detection element DU of the FPD 3 is created, the data line 34 and the gate line 35 are formed on the surface of the insulating substrate 36 by using a thin film forming technique by various vacuum deposition methods or a pattern technique by photolithography. A thin film transistor Tr, a capacitor Ca, a carrier collection electrode 33, a semiconductor thick film 31, a voltage application electrode 32, and the like are sequentially stacked. The semiconductor for forming the semiconductor thick film 31 can be appropriately selected according to the application, withstand voltage, etc., as exemplified by an amorphous semiconductor and a polycrystalline semiconductor.

  Thus, the gate driver circuit 38 has a function of driving the FPD 3 by supplying a drive signal. Therefore, the gate driver circuit 38 corresponds to the driving means in the present invention. The amplifier array circuit 37 includes the A / D converter 8 outside the FPD 3 and has a function of receiving a carrier based on a read signal related to reading of the carrier. The A / D converter 8 and the amplifier array circuit 37 correspond to the reading means in this invention. Note that the A / D converter 8 may be included in the configuration of the FPD 3. The gate driver circuit 38, the amplifier array circuit 37, and the A / D converter 8 are peripheral circuits of the FPD 3.

  In addition, the FPD 3 includes a switching power supply 39 typified by a DC-DC converter. The switching power supply 39 generates a DC voltage and can realize a power supply that is small and has high conversion efficiency. In the first embodiment, the switching power supply 39 supplies power to a readout circuit such as the amplifier array circuit 37 and the A / D converter 8. The switching power supply 39 corresponds to the power supply in the present invention. In the first embodiment, a power source (not shown) that supplies power to the gate driver circuit 38 is provided separately from the switching power source 39.

  As shown in FIG. 3, the control circuit 5 is electrically connected to the gate driver circuit 38, the amplifier array circuit 37, and the A / D converter 8, and is also connected to the switching power supply 39 in the first embodiment. Electrically connected. The switching power supply 39 is electrically connected to the amplifier array circuit 37 and the A / D converter 8 in order to supply power.

  By electrically connecting the control circuit 5 to the gate driver circuit 38, the amplifier array circuit 37, and the A / D converter 8, the control circuit 5 outputs or stops driving signals from the gate driver circuit 38. In addition to controlling, the output and stop of the read signal to the amplifier array circuit 37 and the A / D converter 8 are controlled. In the first embodiment, the control circuit 5 is also electrically connected to the switching power supply 39 so that the switching power supply 39 operates in synchronization with the drive signal from the gate driver circuit 38.

  For comparison with FIG. 3 of the first embodiment, a description will be given with reference to FIG. FIG. 4 is a conventional block diagram. Conventionally, as shown in FIG. 4, the control circuit 5 is electrically connected to the gate driver circuit 38, the amplifier array circuit 37, and the A / D converter 8, and the switching power supply 39 is connected to the amplifier array circuit 37. And A / D converter 8 is electrically connected. This connection mode is the same as that in FIG. 3 of the first embodiment. The difference between FIG. 3 of the first embodiment and the conventional FIG. 4 is that, in the first embodiment, the control circuit 5 is electrically connected to the switching power supply 39 (see FIG. 3). Conventionally, the control circuit 5 is not electrically connected to the switching power supply 39 (see FIG. 4).

  That is, conventionally, the switching power supply 39 supplies power independently to the control circuit 5, the gate driver circuit 38, the amplifier array circuit 37, and the A / D converter 8. Therefore, the switching power supply 39 operates independently of the control circuit 5, the gate driver circuit 38, the amplifier array circuit 37, and the A / D converter 8.

Next, operations of the X-ray fluoroscopic apparatus and the flat panel X-ray detector (FPD) according to the first embodiment will be described. In a state where a bias voltage V _A of a high voltage (for example, about several hundred V to several tens kV) is applied to the voltage application electrode 32, radiation to be detected is incident. The application of the bias voltage V _A is also controlled from the control circuit 5.

  Carriers are generated by the incidence of radiation, and the carriers are stored in the charge storage capacitor Ca as charge information. The gate line 35 is selected by the scanning signal for extracting signals from the gate driver circuit 38 (that is, the gate drive signal), and the detection element DU connected to the selected gate line 35 is selected and designated. The electric charge accumulated in the capacitor Ca of the designated detection element DU is read out to the data line 34 via the thin film transistor Tr that has been turned on by the signal of the selected gate line 35.

  The address (address) of each detection element DU is specified by a scanning signal for extracting signals from the data line 34 and the gate line 35 (a gate drive signal in the case of the gate line 35 and an amplifier drive signal in the case of the data line 34). ). When a scanning signal for signal extraction is sent to the amplifier array circuit 37 and the gate driver circuit 38, each detection element DU is selected from the gate driver circuit 38 in accordance with the scanning signal (gate driving signal) in the longitudinal (Y) direction. Then, the amplifier array circuit 37 is switched in accordance with the scanning signal (amplifier driving signal) in the horizontal (X) direction, whereby the charge accumulated in the capacitor Ca of the selected detection element DU is amplified via the data line 34. It is sent to the circuit 37. Then, the signal is amplified by the amplifier array circuit 37, output from the amplifier array circuit 37 as an X-ray detection signal, and sent to the A / D converter 8.

  For example, when the FPD 3 according to the first embodiment is used for detection of a fluoroscopic X-ray image of an X-ray fluoroscopic imaging apparatus, the charge information (X-ray detection signal) read to the outside through the data line 34 by the above-described operation. ) Is converted into image information and output as a fluoroscopic image.

  Next, an example of an operation sequence of the switching power supply 39 synchronized with the drive signal will be described with reference to FIG. FIG. 5 is a timing chart illustrating an operation sequence of the switching power supply 39 synchronized with the drive signal according to the first embodiment. “TFT” of the drive signal in FIG. 5 indicates ON or OFF of the gate of the thin film transistor Tr. “Amplifier” of the read signal in FIG. 5 indicates a read signal related to the amplifier array circuit 37. “A / D conversion” of the read signal in FIG. 5 indicates a read signal related to the A / D converter 8. The “power supply clock” in FIG. 5 indicates the supply of power from the switching power supply 39 when it is ON, and indicates the stop of power from the switching power supply 39 when it is OFF.

  Further, in “Amplifier” in FIG. 5, “Reset” indicates reset, “Readout” indicates reading, and “Hold” indicates a sampling hold for sampling and holding data of analog values. Further, it is possible to convert from an analog value to a digital value only during the time when it is ON in “A / D conversion”. It should be noted that one line of data line 34 is read out by one switching of “TFT” ON / OFF.

  In the first embodiment, the “power supply clock” operates by switching between ON and OFF in synchronization with the timing when “TFT” shifts from OFF to ON. When the reading of one line of the data line 34 is completed and the “TFT” shifts from OFF to ON again, the “power supply clock” operates by switching ON / OFF again in synchronization therewith. It repeats similarly about the operation | movement after it.

  In this case, when the ON / OFF switching (switching operation) of the “power supply clock” is performed during reading of one line of the data line 34, a ripple voltage is generated as an AC component at the time of switching (FIG. 8). Noise) due to the ripple voltage is superimposed. However, since the “power supply clock” is synchronized with the timing at which “TFT” shifts from OFF to ON, noise having the same amplitude is input every time one data line 34 is read out. Since the noise has the same amplitude, a constant value of noise is input every time the data line 34 is read out. Therefore, when this constant value is set in advance as an offset value, the offset correction unit 9a (see FIG. 1) subtracts the noise amplitude (offset value) from the digitized charge signal detected by the FPD 3 to perform offset correction. By performing this, it becomes possible to remove noise.

  According to the imaging sensor S according to the first embodiment described above, the gate driver circuit 38 that is driven by applying a drive signal (see “TFT” in FIG. 5) to the flat panel X-ray detector (FPD) 3. The control circuit 5 controls the switching power supply 39 to operate in synchronization with the drive signal from the circuit 38, so that each time the drive signal is switched ON or OFF (in the first embodiment, one line of the data line 34). Noise of the same amplitude is input every time (reading drive). If the noise has the same amplitude, for example, the offset correction unit 9a can perform offset correction and remove it. Therefore, even if noise with the same amplitude is mixed, if it is corrected by offset correction or the like, carriers as charge information can be read out accurately.

  Further, according to the fluoroscopic imaging apparatus including the imaging sensor S, the FPD 3 can accurately detect data based on the accurately read carrier, and a series of image processing performed by the image processing unit 9. Imaging can be accurately performed by the processing.

  In the first embodiment, the X-ray imaging apparatus includes an offset correction unit 9a. If such an offset correction 9a is provided, when noise having the same amplitude is input every time the drive signal is switched ON or OFF, the noise can be corrected and removed by the offset correction means. Therefore, even if noise having the same amplitude is mixed, if correction is performed by offset correction, the carrier can be read out accurately, and imaging can be accurately performed by a series of image processing by the image processing 9.

  In the first embodiment, since the switching power supply 39 is adopted as the power source in the present invention, a large-sized noise is easily mixed when the first embodiment is not applied, but a downsized image sensor S can be realized. . Furthermore, by applying the first embodiment, it is possible to realize an imaging sensor S with low noise and a reduced size.

Next, Embodiment 2 of the present invention will be described with reference to the drawings.
FIG. 6 is a timing chart illustrating a 39 operation sequence of the switching power supply synchronized with the drive signal or the read signal according to the second embodiment. The portions common to the first embodiment are denoted by the same reference numerals and are not illustrated, and the description thereof is omitted. The flat panel X-ray detector (FPD) 3, the imaging sensor S, and the X-ray fluoroscopic apparatus have the same configuration as that shown in FIGS.

  The second embodiment is different from the first embodiment described above in that the power operates so as to synchronize with timing other than the timing sensitive to noise. Therefore, as shown in FIG. 6, the power from the switching power supply 39 is stopped at a timing sensitive to noise, and the power is supplied from the switching power supply 39 at other timings.

  In the second embodiment, (A) amplifier reset end, (B) TFT ON / OFF transition time, (C) amplifier (amplifier array circuit 37) readout period, (D) analog data hold period (analog value) (Sampling hold period during which data is sampled and held) and (E) A / D conversion (A / D converter 8) power is supplied from the switching power supply 39 only at a time other than the time (in FIG. 6). (Refer to “ON” of “Power supply clock”.) In addition, each timing of (A) to (E), that is, a timing at which power is to be stopped from the switching power supply 39 is illustrated by hatching in the right oblique line in FIG. Each timing of (A) to (E) except (B) relates to the read signal, and (B) relates to the drive signal. Therefore, when synchronizing with any timing of (A) to (E) except (B), the switching power supply 39 is also synchronized with the read signal, and when synchronizing with the timing of (B). The switching power supply 39 is also synchronized with the drive signal.

  In particular, the timing of sampling the readout data related to the carrier that is the charge information (see (D) above) and the timing of A / D conversion (see (E) above) for converting from an analog value to a digital value are noises. Become the most sensitive. Timings (A) to (E) including these (D) and (E) are sensitive to noise. Therefore, since it is not sensitive to noise at other timings, the low-noise imaging sensor S can be realized if the power supply operates so as to be synchronized with other timings. As a result, carriers that are charge information can be accurately read.

  The present invention is not limited to the above-described embodiment, and can be modified as follows.

  (1) In each of the above-described embodiments, the X-ray fluoroscopic apparatus as shown in FIG. 1 has been described as an example. However, the present invention may be applied to an X-ray fluoroscopic apparatus disposed on a C-type arm, for example. You may apply. The present invention may also be applied to an X-ray CT apparatus.

  (2) In each of the above-described embodiments, the present invention is applied to a “direct conversion type” radiation detector in which incident radiation is directly converted into charge information by the semiconductor thick film 31 (semiconductor layer). Even if the present invention is applied to an "indirect conversion type" radiation detector that converts radiation into light by a conversion layer such as a scintillator and converts the light into charge information by a semiconductor layer formed of a photosensitive material. Good. The photosensitive semiconductor layer may be formed of a thick film similar to the above-described embodiment, or may be formed of a photodiode.

  (3) In each of the above-described embodiments, the X-ray detector for detecting X-rays has been described as an example. However, in the present invention, a radioisotope (RI) is administered like an ECT (Emission Computed Tomography) apparatus. The radiation detector is not particularly limited as long as it is a radiation detector that detects radiation, as exemplified by a γ-ray detector that detects γ-rays emitted from the subject. Similarly, the present invention is not particularly limited as long as it is an apparatus that performs imaging by detecting radiation, as exemplified by the ECT apparatus described above.

  (4) In each of the above-described embodiments, the radiation detector typified by X-rays has been described as an example. However, the present invention can also be applied to a photodetector that detects light. Therefore, the device is not particularly limited as long as the device detects light and performs imaging.

  (5) In each of the above-described embodiments, the switching power supply 39 that operates in synchronization with the drive signal or readout signal (synchronization with only the drive signal in Embodiment 1) reads out the amplifier array circuit 37 and the A / D converter 8. Although the power source is used to supply power to the means, power may be supplied only to the amplifier array circuit 37, and power may be supplied to the gate driver circuit 38 in addition to the amplifier array circuit 37 and the A / D converter 8. May be supplied. That is, reading is performed based on driving means (gate driver circuit 38) that drives a light or radiation detector represented by FPD3 or the like by driving it and a readout signal related to readout of carriers that are charge information. If power is supplied to at least one of the reading means (amplifier array circuit 37 and A / D converter 8) that receives the received carrier, a specific power supply destination to the driving means or the reading means Is not particularly limited. In addition, a specific signal as a basis of synchronization is not particularly limited as long as the switching power supply 39 operates in synchronization with at least one of the drive signal and the readout signal. Of course, the switching power supply 39 may operate in synchronization with both the drive signal and the read signal.

  (6) In each of the above-described embodiments, the X-ray imaging apparatus typified by the X-ray fluoroscopic apparatus includes the offset correction unit 9a. The correction means is not particularly limited. Further, if the power source represented by the switching power source 39 or the like is operated so as to synchronize with a timing that is not sensitive to noise as in the above-described second embodiment, noise such as ripple is reduced, so that offset correction is not necessarily performed. Correction means such as the portion 9a is not necessary.

  (7) In each of the above-described embodiments, the power source that operates in synchronization with the drive signal or the read signal is the switching power source 39. However, as exemplified by a dropper type power source, the type of power source is particularly limited. Not. In the case of a switching power supply such as the switching power supply 39 as in each embodiment, the present invention is particularly useful because it can reduce noise.

  (8) When a period in which the power source represented by the switching power source 39 is not driven continues for a long time, that is, when the supply of power from the power source continues to stop for a long time, power is supplementally supplied via a capacitor or a battery. You may comprise.

  (9) In the first embodiment described above, a power source represented by the switching power supply 39 operates in synchronization with the timing at which the gate of the thin film transistor Tr shifts from OFF to ON. In the second embodiment described above, noise is sensitive. The power supply operates in synchronization with a timing other than the timing, but is not particularly limited as long as it relates to a drive signal or a read signal. For example, as shown in FIG. 7, when reading one frame, when a line other than reading of each line (“reading period” in FIG. 7) is set as a “blanking period”, the power is supplied only during the blanking period. May be operated (in FIG. 7, “power supply clock” is repeatedly switched ON / OFF).

1 is a block diagram of an X-ray fluoroscopic apparatus according to each embodiment. 2 is an equivalent circuit of a flat panel X-ray detector as viewed from the side, which is used in an X-ray fluoroscopic apparatus. 2 is an equivalent circuit of a flat panel X-ray detector in plan view. FIG. 4 is a conventional block diagram used for comparison with FIG. 3. 3 is a timing chart showing an operation sequence of the switching power supply synchronized with the drive signal according to the first embodiment. 10 is a timing chart illustrating an operation sequence of a switching power supply that is synchronized with a drive signal or a read signal according to the second embodiment. It is a timing chart which shows the operation | movement sequence of the switching power supply which synchronizes with the drive signal which concerns on a modification. It is a timing chart regarding the ripple which generate | occur | produces at the time of switching ON / OFF of a power supply internal circuit.

Explanation of symbols

3 ... Flat panel X-ray detector (FPD)
DESCRIPTION OF SYMBOLS 5 ... Control circuit 9 ... Image processing part 9a ... Offset correction part 37 ... Amplifier array circuit 38 ... Gate driver circuit 39 ... Switching power supply S ... Imaging sensor

Claims (4)

  The light or radiation information is converted into charge information by the incidence of light or radiation, the light or radiation detector detects the light or radiation by reading out the converted charge information, and a drive signal is given to the detector. Power is supplied to at least one of the driving means that drives the reading means, the reading means that receives the read charge information, and the driving means and the reading means based on a read signal related to reading the charge information An image sensor including a power supply for controlling the power supply to operate in synchronization with at least one of a drive signal from the drive means and a read signal to the readout means. An imaging sensor comprising:   The imaging sensor according to claim 1, wherein the power source is a switching power source that generates a DC voltage.   An imaging apparatus using the imaging sensor according to claim 1 or 2, wherein the apparatus includes the imaging sensor and image processing means for performing image processing, and the imaging sensor is configured to emit light or radiation. Light or radiation detector that converts the light or radiation information into charge information upon incidence, and detects the light or radiation by reading the converted charge information, and a drive that drives the detector by supplying a drive signal. Means, a reading means for receiving the read charge information based on a read signal related to the reading of the charge information, and a power source for supplying power to at least one of the driving means and the reading means. And in synchronization with at least one of a drive signal from the drive means and a read signal to the readout means. The image processing means includes control means for performing control for operating a power supply, and the image processing means performs image processing based on data detected by the light or radiation detector, and detection by the detector and image processing by an image processing unit An imaging device that performs imaging by a series of processes. 4. The imaging apparatus according to claim 3, further comprising an offset correction unit that performs offset correction on data detected by the light or radiation detector.

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