JP2011223088A - Imaging apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an imaging apparatus in which temperature-measuring means is disposed easily and imaging can be performed while determining an amount of dark signals accurately.SOLUTION: A temperature sensor 10 is disposed on a base plate 41 on which an X-ray conversion layer 23, and the like, are held, and the temperature sensor 10 obtains in-plane distribution information about a temperature around the X-ray conversion layer 23 by measuring the temperature around the X-ray conversion layer 23 a plurality of times. Therefore, the temperature can be determined accurately even in a region remote from a place where the temperature sensor 10 is provided, and a function for calculating the amount of dark signals can determine the amount of dark signals accurately based on the correlation between the amount of dark signals and the in-plane distribution information about the temperature around the X-ray conversion layer 23 when the amount of dark signals is obtained, and the in-plane distribution information about the temperature around the X-ray conversion layer 23 measured by the temperature sensor 10.

Description

  The present invention relates to an imaging apparatus used in the medical field, the industrial field, the nuclear field, and the like.

  An imaging device that obtains an image based on charge information will be described taking an example in which X-rays are incident and converted into charge information. The imaging apparatus includes an X-ray sensitive X-ray conversion layer, and the X-ray conversion layer converts into carriers (charge information) by the incidence of X-rays. A CdTe film is used as the X-ray conversion layer.

  In addition, the imaging device includes a circuit that accumulates and reads out carriers converted by the X-ray conversion layer. As shown in FIG. 11, this circuit is composed of a plurality of gate lines G and data lines D arranged two-dimensionally, and turns on a capacitor Ca for accumulating carriers and a carrier accumulated in the capacitor Ca. Thin film transistors (TFTs) Tr that are read out by switching between / OFF are arranged in a two-dimensional manner. The gate line G controls ON / OFF switching of each thin film transistor Tr and is electrically connected to the gate of each thin film transistor Tr. The data line D is electrically connected to the reading side of the thin film transistor Tr.

  Each detection element is constituted by each capacitor Ca, each thin film transistor Tr, and the like. By selecting the gate line G, the detection element electrically connected to the selected gate line G is driven to generate a carrier. Is read out. By the way, regardless of the time of X-ray irradiation, dark current exists even when X-rays are not irradiated, and the dark current at the time of non-irradiation is read as a dark signal (also referred to as “dark current signal”). Conventionally, there is a method of reading out and measuring a dark signal regardless of the temperature of the X-ray conversion layer and subtracting the dark signal amount (see, for example, Patent Document 1).

JP 2006-305228 A

  However, in the conventional method described above, it is necessary to embed a temperature sensor in the X-ray conversion layer in order to measure the temperature of the X-ray conversion layer. Therefore, the present inventors have previously proposed the technology of the international application PCT / JP2009 / 001388. In this technique, as shown in FIG. 12A or 12B, when the carrier collection electrode 122, the X-ray conversion layer 123, the voltage application electrode 124, and the like are sequentially stacked on the surface of the insulating substrate 121, In order to measure the temperature of the X-ray conversion layer 123, the temperature sensor 110 is provided on the voltage application electrode 124 at an end portion that is outside a detection effective area (not shown). Then, the dark signal amount is obtained using the temperature measured by the temperature sensor 110 as the temperature around the X-ray conversion layer 123.

However, this technique has a structure in which a temperature sensor is provided only at an end portion outside the effective detection area, and thus the temperature of the X-ray conversion layer cannot be accurately obtained. Further, the temperature in the pixel region far from the detection effective area is different from the temperature measured by the temperature sensor, and the dark signal amount in the pixel region cannot be accurately obtained. Therefore, there is a problem that correction for subtracting the dark signal amount does not work.
The present invention has been made in view of such circumstances, and it is an object of the present invention to provide an image pickup apparatus that can easily arrange a temperature measurement means and accurately obtain a dark signal amount to perform image pickup. Objective.

In order to achieve such an object, the present invention has the following configuration.
That is, an imaging device according to the present invention includes a conversion layer that converts light or radiation information into charge information upon incidence of light or radiation, and a storage / readout circuit that stores and reads out charge information converted by the conversion layer. An imaging device that obtains an image based on charge information read by the storage / readout circuit, and measures a plurality of temperatures around the conversion layer in a predetermined plane around the conversion layer A temperature measuring means for obtaining in-plane distribution information relating to the temperature around the conversion layer; a dark signal amount equivalent to a charge when no light or radiation is irradiated; and a temperature around the conversion layer when the dark signal amount is obtained. Based on the correlation with the in-plane distribution information and the in-plane distribution information regarding the temperature around the conversion layer measured by the temperature measuring unit, the dark signal amount calculating means for obtaining the dark signal amount, Is characterized in further comprising a correction means for correcting the charge information at the time of irradiation based on the dark signal amount obtained using the clock signal amount calculating means.

  [Operation / Effect] According to the imaging apparatus of the present invention, the temperature measuring means can be easily disposed at a place other than the conversion layer by using the temperature around the conversion layer instead of the temperature of the conversion layer. . In addition, the temperature measurement means is provided because the temperature measurement means obtains in-plane distribution information relating to the temperature around the conversion layer by measuring the temperature around the conversion layer in a plurality of predetermined planes around the conversion layer. The temperature can be accurately obtained even in a region away from the location. Therefore, the correlation between the dark signal amount and the in-plane distribution information about the temperature around the conversion layer when the dark signal amount is obtained, and the in-plane distribution information about the temperature around the conversion layer measured by the temperature measuring means Based on this, the dark signal amount calculation means can accurately determine the dark signal amount. To summarize the above, it is possible to easily arrange the temperature measuring means and accurately obtain the dark signal amount to perform imaging.

  In the above-described invention, it is preferable to provide correlation storage means for storing the above-described correlation in advance. The correlation may be a table in which the dark signal amount and the in-plane distribution information regarding the temperature around the conversion layer when the dark signal amount is obtained, or the dark signal amount and the dark signal. An approximate expression related to the in-plane distribution information related to the temperature around the conversion layer when the quantity is obtained may be programmed.

  In these inventions described above, it is preferable to include temperature interpolation means for interpolating the temperature at the location where the temperature measurement means is not provided using the temperature at the location where the temperature measurement means is provided. The temperature can be accurately obtained by interpolating the temperature with the temperature interpolation means while reducing the number of temperature measurement means to be provided in the plane.

  In the above-described inventions, the above correlation is an approximate expression related to the dark signal amount and the in-plane distribution information related to the temperature around the conversion layer, and stores the in-plane distribution information related to the coefficients used in the approximate expression. Coefficient in-plane distribution information storage means may be provided. The coefficients used in the approximate expression are not uniform in the plane, and there are variations in the plane. Therefore, the characteristics of the approximate expression also vary within the plane. Therefore, by providing the coefficient in-plane distribution information storage means for storing the in-plane distribution information regarding the coefficients, the dark signal amount can be determined more accurately even if the characteristics of the approximate expression vary in the plane. Note that, similarly to the above-described correlation storage unit, a table in which each location in the plane is associated with a coefficient at the location may be used.

  In these inventions described above, the temperature measuring means may be disposed on the structure provided on the side opposite to the light or radiation incident side of the conversion layer, or provided on the light or radiation incident side of the conversion layer. A temperature measuring means may be provided in the structure. Of course, the temperature measuring means is disposed on the structure provided on the opposite side to the incident side as in the former, and the structure provided on the light or radiation incident side of the conversion layer as in the latter. A temperature measuring means may be provided to combine the former and the latter.

  As in the former case, when the temperature measuring means is disposed on the structure provided on the opposite side to the incident side, the temperature measuring means does not hinder the incidence of light or radiation. It can be provided at a location. Therefore, temperature measuring means may be disposed also in the effective detection area of light or radiation of the structure. As described above, by arranging the temperature measuring means also in the effective detection area, the temperature in the effective detection area can be accurately determined, and the dark signal amount in the effective detection area can be accurately determined.

  An example of the arrangement of the temperature measuring means when viewed from the incident is as described above, but an example of the arrangement of the temperature measuring means when viewed from a specific structure other than the incident is as follows.

  That is, a holding member that holds the conversion layer and the storage / readout circuit may be provided, and temperature measuring means may be provided on the holding member. Usually, since the holding member is often provided on the side opposite to the incident side, it is possible to dispose the temperature measuring means also in the detection effective area of the holding member. Of course, the present invention can also be applied when light or radiation is incident from the holding member.

  Further, a substrate for patterning the storage / readout circuit may be provided, and temperature measuring means may be provided on the substrate. Of course, in combination with the above-described holding member, the temperature measuring means may be provided on the holding member and the temperature measuring means may be provided on the substrate.

  In addition, a voltage application electrode for applying a bias voltage may be provided, and a temperature measuring unit may be provided on the voltage application electrode. Of course, in combination with the above-described holding member or substrate, temperature measuring means may be provided on the holding member, or temperature measuring means may be provided on the substrate, and temperature measuring means may be provided on the voltage application electrode.

  Alternatively, the conversion layer and the storage / readout circuit may be sealed with an insulator, and temperature measuring means may be disposed on the sealed insulator. Of course, in combination with the above-described holding member, substrate, or voltage application electrode, the temperature measurement means is arranged on the holding member, the temperature measurement device is arranged on the substrate, or the temperature measurement means is arranged on the voltage application electrode, and also insulated. The object may be provided with temperature measuring means.

  According to the imaging device of the present invention, the temperature measurement unit obtains in-plane distribution information related to the temperature around the conversion layer by measuring the temperature around the conversion layer in a plurality of areas within a predetermined plane around the conversion layer. The temperature can be accurately obtained even in a region away from the place where the temperature measuring means is provided, and the dark signal amount and the in-plane distribution information regarding the temperature around the conversion layer when the dark signal amount is obtained. Based on the correlation and the in-plane distribution information regarding the temperature around the conversion layer measured by the temperature measuring unit, the dark signal amount calculating unit can accurately determine the dark signal amount. As a result, it is possible to easily arrange the temperature measuring means and accurately obtain the dark signal amount to perform imaging.

It is a schematic block diagram of the X-ray imaging apparatus which concerns on each Example. 1 is a schematic cross-sectional view around an X-ray conversion layer of an X-ray imaging apparatus. 2 is a peripheral circuit diagram of a charge-voltage conversion amplifier and an A / D converter of an X-ray imaging apparatus. FIG. 1 is a schematic cross-sectional view of a structure in which an X-ray conversion layer, a detection element circuit, and the like of an X-ray imaging apparatus according to Embodiment 1 are molded and sealed. It is a form when a temperature sensor is provided on the base plate according to the first embodiment. It is the table | surface which showed typically the in-plane distribution information regarding the coefficient used by an approximate expression. It is the figure which showed typically the in-plane distribution information regarding the temperature with which it uses for description of temperature interpolation. It is a schematic sectional drawing of the structure which mold-sealed the X-ray conversion layer of the X-ray imaging apparatus which concerns on Example 2, and the circuit for detection elements. It is a schematic sectional drawing of the structure which mold-sealed the X-ray conversion layer of the X-ray imaging apparatus which concerns on Example 3, and the circuit for detection elements. It is a schematic sectional drawing of the structure which mold-sealed the X-ray conversion layer of the X-ray imaging apparatus which concerns on Example 4, the circuit for detection elements, etc. FIG. It is a schematic block diagram of the conventional X-ray imaging apparatus. (A), (b) is a schematic sectional drawing of the X-ray conversion layer periphery of the X-ray imaging apparatus of the technique proposed previously.

Embodiment 1 of the present invention will be described below with reference to the drawings.
FIG. 1 is a schematic block diagram of the X-ray imaging apparatus according to the first embodiment, FIG. 2 is a schematic cross-sectional view around the X-ray conversion layer of the X-ray imaging apparatus, and FIG. It is a peripheral circuit diagram of a charge-voltage conversion amplifier and an A / D converter. In Example 1, including Examples 2 to 4 described later, X-rays will be described as an example of incident radiation, and an X-ray imaging apparatus will be described as an example of the imaging apparatus.

  The X-ray imaging apparatus according to the first embodiment including Examples 2 to 4 described later performs imaging by irradiating the subject with X-rays. Specifically, an X-ray image transmitted through the subject is projected onto an X-ray conversion layer (CdTe film in the first embodiment), and carriers (charge information) proportional to the density of the image are generated in the layer. Is converted into a carrier.

  As shown in FIG. 1, the X-ray imaging apparatus accumulates and reads out carriers converted by a gate drive circuit 1 that selects a gate line G, which will be described later, and an X-ray conversion layer 23 (see FIG. 2). A detection element circuit 2 that detects X-rays, a charge-voltage conversion amplifier 3 that amplifies the carrier read out by the detection element circuit 2 into a voltage, and the charge-voltage conversion amplifier 3 An A / D converter 4 for converting a voltage analog value into a digital value, and an image processing unit 5 for obtaining an image by performing signal processing on the voltage value converted into a digital value by the A / D converter 4; The controller 6 that controls the circuits 1 and 2, the charge / voltage conversion amplifier 3, the A / D converter 4, the image processing unit 5, the memory unit 7 and the monitor 9 described later, and the processed image are stored. Memory unit 7 and input An input unit 8 which performs a constant, and a monitor 9 for displaying the processed images. In this specification, information such as a carrier and an image is image information related to the image. The X-ray conversion layer 23 corresponds to the conversion layer in the present invention, and the detection element circuit 2 corresponds to the storage / readout circuit in the present invention.

  The gate drive circuit 1 is electrically connected to a plurality of gate lines G. By applying a voltage from the gate driving circuit 1 to each gate line G, a thin film transistor (TFT) Tr described later is turned on to release reading of carriers accumulated in a capacitor Ca described later, and the voltage applied to each gate line G Is stopped (the voltage is set to −10 V), and the thin film transistor Tr is turned off to block carrier reading. Note that the thin film transistor Tr is turned off by applying a voltage to each gate line G to cut off carrier reading and stopping the voltage to each gate line G to turn on and release carrier reading. It may be configured.

  The detection element circuit 2 includes a plurality of gate lines G and data lines D arranged in a two-dimensional manner, and switches the capacitor Ca that accumulates carriers and the carriers accumulated in the capacitor Ca to ON / OFF. The thin film transistors Tr to be read out are arranged in a two-dimensional manner. The gate line G controls ON / OFF switching of each thin film transistor Tr and is electrically connected to the gate of each thin film transistor Tr. The data line D is electrically connected to the reading side of the thin film transistor Tr.

  For convenience of explanation, it is assumed that 10 × 10 thin film transistors Tr and capacitors Ca are formed in a vertical and horizontal two-dimensional matrix arrangement in the first embodiment, including later-described second to fourth embodiments. That is, the gate line G is composed of ten gate lines G1 to G10, and the data line D is composed of ten data lines D1 to D10. The gate lines G1 to G10 are respectively connected to the gates of ten thin film transistors Tr arranged in parallel in the X direction in FIG. 1, and the data lines D1 to D10 are arranged in parallel in the Y direction in FIG. Each of the ten thin film transistors Tr is connected to the reading side. A capacitor Ca is electrically connected to the side opposite to the reading side of the thin film transistor Tr, and the number of the thin film transistor Tr and the capacitor Ca corresponds one to one.

  In the detection element circuit 2, as shown in FIG. 2, the detection elements DU are patterned on the insulating substrate 21 in a two-dimensional matrix arrangement. That is, the gate lines G1 to G10 and the data lines D1 to D10 described above are wired on the surface of the insulating substrate 21 by using a thin film forming technique by various vacuum deposition methods and a pattern technique by a photolithography method. Ca, the carrier collection electrode 22, the X-ray conversion layer 23, and the voltage application electrode 24 are laminated in order. The insulating substrate 21 corresponds to the substrate in the present invention, and the voltage application electrode 24 corresponds to the voltage application electrode in the present invention.

  The X-ray conversion layer 23 is formed of an X-ray sensitive semiconductor thick film, and is formed of a CdTe film in the present embodiment 1, including later-described embodiments 2 to 4. The X-ray conversion layer 23 converts X-ray information into carriers as charge information by the incidence of X-rays. The X-ray conversion layer 23 is not limited to CdTe as long as it is an X-ray sensitive material in which carriers are generated by the incidence of X-rays. In addition, when imaging is performed by injecting radiation other than X-rays (such as γ-rays), a radiation-sensitive material that generates carriers by the incidence of radiation may be used instead of the X-ray conversion layer 23. Good. Further, when imaging is performed with light incident, instead of the X-ray conversion layer 23, a photosensitive material that generates carriers by the incidence of light may be used.

  The carrier collection electrode 22 is electrically connected to the capacitor Ca, collects the carrier converted by the X-ray conversion layer 23 and accumulates it in the capacitor Ca. Similarly to the thin film transistor Tr and the capacitor Ca, a large number (10 × 10 in the first embodiment) of the carrier collection electrodes 22 are formed in a vertical / horizontal two-dimensional matrix arrangement. The carrier collecting electrode 22, the capacitor Ca, and the thin film transistor Tr are separately formed as each detecting element DU. Further, the voltage application electrode 24 is formed over the entire surface as a common electrode of all the detection elements DU.

  In addition to Example 2-4 mentioned later, in this Example 1, the temperature sensor 10 which measures the temperature of the X-ray conversion layer 23 is provided. The measurement result by the temperature sensor 10 is sent to the controller 6. The temperature sensor 10 corresponds to the temperature measuring means in this invention.

  In order to measure the temperature of the X-ray conversion layer 23, the temperature sensor 10 is provided in a predetermined plane around the X-ray conversion layer 23 without providing the temperature sensor in the X-ray conversion layer 23. In the first embodiment, a temperature sensor 10 is provided as shown in FIGS. 4 and 5 described later. The arrangement of the temperature sensor 10 will be described in detail later with reference to FIGS.

  As shown in FIG. 3, the charge-voltage conversion amplifier 3 is electrically connected to each data line D (D1 to D10 in FIG. 3) and electrically connected to each data line D. Amplifier capacitor 32, amplifier 31 for each data line D, sample hold 33 electrically connected in parallel to amplifier capacitor 32, and switching element 34 electrically connected to sample hold 33 for each data line D And. The amplifier 31 and the end of the data line D of the detection element circuit 2 are electrically connected to each data line D via the switching element SW. The carrier read to the data line D is turned on by the switching element SW and sent to the amplifier 31 and the amplifier capacitor 32 of the charge-voltage conversion amplifier 3. The supplied carrier is amplified with the amplifier 31 and the amplifier capacitor 32 converted into a voltage, and the sample hold 33 temporarily accumulates the amplified voltage value for a predetermined time. The voltage value once accumulated is sent to the A / D converter 4 with the switching element 34 turned ON, and the A / D converter 4 converts the analog value of the sent voltage into a digital value.

  Returning to the description of FIG. 1, the image processing unit 5 performs various signal processing on the voltage value converted into a digital value by the A / D converter 4 to obtain an image. The controller 6 comprehensively controls the circuits 1 and 2, the charge / voltage conversion amplifier 3, the A / D converter 4, the image processing unit 5, a memory unit 7 and a monitor 9 which will be described later, and in this embodiment (1) X The carrier (that is, dark current) at the time of non-irradiation of the line is acquired as the dark signal amount, and the dark signal amount and the in-plane distribution information regarding the temperature around the X-ray conversion layer 23 when the dark signal amount is obtained. Based on the correlation and in-plane distribution information regarding the temperature around the X-ray conversion layer 23 measured by the temperature sensor 10, a function for obtaining a dark signal amount (a function for calculating a dark signal amount), (2) the temperature sensor 10 The function of interpolating the temperature at the location where the temperature sensor 10 is provided using the temperature at the location where the temperature sensor 10 is provided (temperature interpolation function) and (3) the dark signal obtained by the function of calculating the dark signal amount Key for irradiation based on the amount Also it has a rear function of correcting (charge information) (Function of correction). The image processing unit 5 and the controller 6 are configured by a combination of a central processing unit (CPU) and a programmable logic device (FPGA). The controller 6 corresponds to dark signal amount calculation means, temperature interpolation means, and correction means in the present invention.

  The memory unit 7 writes and stores image information and the like, and the image information and the like are read from the memory unit 7 in response to a read command from the controller 6. The memory unit 7 includes a storage medium represented by ROM (Read-only Memory), RAM (Random-Access Memory), and the like. Note that a RAM is used for writing image information. For example, when the controller 6 executes the control sequence by reading a program related to the control sequence, a ROM is used exclusively for reading the program related to the control sequence. In the first embodiment, the dark signal amount is obtained based on the above correlation and the in-plane distribution information regarding the temperature around the X-ray conversion layer 23 measured by the temperature sensor 10, the temperature is interpolated, and the carrier at the time of irradiation is obtained. Is stored in the memory unit 7 and the control sequence is executed by the controller 6 by reading the program.

  In addition, the memory unit 7 includes in-plane distribution information regarding the correlation memory unit 7a that stores the above-described correlations in advance, and coefficients (here, constants α and β) used in an approximate expression of the following equation (1). The coefficient in-plane distribution information memory unit 7b is stored. The correlation memory unit 7a corresponds to the correlation storage unit in the present invention, and the coefficient in-plane distribution information memory unit 7b corresponds to the coefficient in-plane distribution information storage unit in the present invention.

  The input unit 8 includes a pointing device represented by a mouse, a keyboard, a joystick, a trackball, a touch panel, or the like, or an input means such as a button, a switch, or a lever. When input is set in the input unit 8, input setting data is sent to the controller 6, and based on the input setting data, the circuits 1, 2, the charge / voltage conversion amplifier 3, the A / D converter 4, the image processing unit 5 and the memory unit 7 And the monitor 9 are controlled.

Subsequently, a control sequence of the X-ray imaging apparatus according to the first embodiment will be described. X-rays to be detected are incident on the voltage application electrode 24 with a high voltage (for example, several tens of volts to several hundreds of volts) bias voltage _VA applied thereto.

  Carriers are generated in the X-ray conversion layer 23 by the incidence of X-rays, and the carriers are accumulated in the capacitor Ca through the carrier collection electrode 22 as charge information. A target gate line G is selected by a scanning signal (that is, a gate driving signal) for reading a signal (here, carrier) of the gate driving circuit 1. In the present embodiment 1, including later-described embodiments 2 to 4, description will be made assuming that gate lines G1, G2, G3,..., G9, G10 are selected one by one in order. The scanning signal for reading signals from the gate driving circuit 1 is a signal for applying a voltage (for example, about 15 V) to the gate line G.

  A target gate line G is selected from the gate drive circuit 1, and each thin film transistor Tr connected to the selected gate line G is selected and designated. A voltage is applied to the gate of the thin film transistor Tr selected and designated by this selection designation to turn on. Carriers accumulated from the capacitors Ca connected to the selected and designated thin film transistors Tr are read out to the data line D via the thin film transistors Tr that have been designated and designated to be turned on. That is, the detection element DU related to the selected gate line G is selected and designated, and carriers accumulated in the capacitor Ca of the selected and designated detection element DU are read out to the data line D.

  Specifically, the amplifier 31 of the charge-voltage conversion amplifier 3 connected to the data line D is reset, and the thin film transistor Tr is turned on (that is, the gate is turned on). It is read out and amplified in a state converted into a voltage by the amplifier 31 and the amplifier capacitor 32 of the charge-voltage conversion amplifier 3.

  That is, the address (address) designation of each detection element DU is performed based on the scanning signal for signal reading from the gate drive circuit 1 and the selection of the amplifier 31 connected to the data line D.

  First, the gate line G1 is selected from the gate drive circuit 1, the detection element DU related to the selected gate line G1 is selected and specified, and the carriers accumulated in the capacitor Ca of the selected and specified detection element DU are all stored. Data line D is read out simultaneously, and after sample hold, data lines D1 to D10 are converted into digital values by A / D converter 4 in this order. Next, the gate line G2 is selected from the gate drive circuit 1, and the detection element DU related to the selected gate line G2 is selected and specified in the same procedure, and is stored in the capacitor Ca of the selected detection element DU. All the data lines D are read out simultaneously, and after sample-holding, the data lines D1 to D10 are converted into digital values by the A / D converter 4 in this order. Similarly, the remaining gate lines G are sequentially selected to read out a two-dimensional carrier.

  Each read carrier is amplified in a state of being converted into a voltage by an amplifier 31 and an amplifier capacitor 32, temporarily stored in a sample hold 33, and converted from an analog value to a digital value by an A / D converter 4. Is done. Based on the voltage value converted into the digital value, the image processing unit 5 performs various signal processing to obtain a two-dimensional image. The obtained two-dimensional image and image information represented by a carrier are written and stored in the memory unit 7 via the controller 6 and are read from the memory unit 7 via the controller 6 as necessary. Further, the image information is displayed on the monitor 9 via the controller 6.

  Next, an arrangement form of the temperature sensor 10 will be described with reference to FIGS. 4 and 5. FIG. 4 is a schematic cross-sectional view of a structure in which the X-ray conversion layer, the detection element circuit, and the like of the X-ray imaging apparatus according to the first embodiment are mold-sealed, and FIG. 5 illustrates the base plate according to the first embodiment. It is a form when a temperature sensor is provided.

  As described in FIG. 2, as shown in FIG. 4, the insulating substrate 21, the X-ray conversion layer 23, and the voltage application electrode 24 on which detection elements DU (see FIG. 2) and the like are patterned in a two-dimensional matrix arrangement They are stacked in order. In the detection element circuit 2, pattern formation (gate lines G1 to G10, data lines D1 to D10, thin film transistors Tr, capacitors Ca, carrier collection electrodes 22 and the like of the detection elements DU) is not shown in FIG. The detection element circuit 2 including these X-ray conversion layers 23 is also called a flat panel X-ray detector (FPD).

  As shown in FIG. 4, a frame 42 that surrounds the X-ray conversion layer 23 and the like from its periphery is attached on a base plate 41 that holds the detection element circuit 2, and the upper cover glass 43 is supported by the frame 42 to support the FPD. Is protecting. Then, the curable synthetic resin is poured into the space between the upper cover glass 43 and the FPD to mold-seal the X-ray conversion layer 23, the detection element circuit 2, and the like. Reference numeral 44 denotes a resin film in which a curable synthetic resin is poured, and reference numeral A denotes a detection effective area in a region inside the region where the voltage application electrode 24 is formed. Image information in the effective detection area A can be obtained by performing imaging by injecting X-rays into the effective detection area A. The base plate 41 corresponds to the holding member in the present invention, and the resin film 44 corresponds to the insulator in the present invention.

  The material of the base plate 41 is not particularly limited as long as it is a material that can be held, but it is preferable to use lightweight aluminum as the base plate 41 in consideration of electromagnetic shielding and temperature uniformity. In addition, it is preferable to adjust the temperature of the base plate 41 so as to maintain a constant temperature so as to equalize the X-ray conversion layer 23 (for example, a CdTe film). For temperature adjustment, for example, water cooling or a Peltier element is employed.

  In the case of the structure of FIG. 4, the X-rays enter the upper cover glass 43 side, and the X-rays enter the X-ray conversion layer 23 through the upper cover glass 43. Accordingly, when viewed from the X-ray conversion layer 23, the resin film 44, the voltage application electrode 24, and the like are on the X-ray incident side of the X-ray conversion layer 23, and the insulating substrate 21, the base plate 41, and the like are It is on the opposite side to the incident side of the line.

  In the first embodiment, a place where the temperature sensor 10 that is a temperature measuring unit is disposed is a structure provided on the side opposite to the incident side, and a base plate 41 that is a holding member is used as the structure. Therefore, the temperature sensor 10 is provided on the base plate 41. In order to obtain in-plane distribution information relating to the temperature around the X-ray conversion layer 23, a plurality of temperature sensors 10 are provided. As shown in FIGS. 4 and 5, in the first embodiment, the temperature sensors 10 are provided at the four corners of the base plate 41 near the end of the X-ray conversion layer 23 outside the effective detection area A, and as shown in FIG. The temperature sensor 10 is also provided in the central area in the effective detection area A.

  As for the arrangement form of the temperature sensor 10, as shown in FIG. 4, the temperature sensor 10 may be embedded in the base plate 41, or the temperature sensor 10 is placed on the surface of the base plate 41 (for example, the surface opposite to the incident side). It may be adhered. Further, the location where the temperature sensor 10 is provided is not necessarily limited to the central region of the effective detection area A, and one or more temperature sensors 10 may be provided in other regions of the effective detection area A, or in addition to other regions. The temperature sensor 10 may also be provided in the central region. Further, the temperature sensor 10 is not limited to the four corners outside the effective detection area A where the temperature sensor 10 is provided, and the temperature sensor 10 may be provided at an arbitrary position outside the effective detection area A, and at least one of the four corners in addition to the arbitrary position. A crab temperature sensor 10 may be provided.

  Next, a series of control sequences will be described with reference to FIGS. FIG. 6 is a table schematically showing the in-plane distribution information regarding the coefficients used in the approximate expression, and FIG. 7 is a diagram schematically showing the in-plane distribution information regarding the temperature used for explanation of the temperature interpolation. is there.

  The dark signal mainly includes an offset component of the amplifier 31 that does not depend on the temperature change of the X-ray conversion layer 23 and a conversion layer leak component that depends on the temperature change of the X-ray conversion layer 23. In the following description, only the conversion layer leak component is described for the dark signal, and correction for the conversion layer leak component is described. In addition, correction regarding the offset component of the amplifier 31 that does not depend on the temperature change is already corrected by subtracting the offset component from the carrier at the time of irradiation.

  While measuring the temperature around the X-ray conversion layer 23 with the temperature sensor 10 disposed on the base plate 41 in advance, the carrier at the time of non-irradiation is read as a dark signal to acquire the dark signal amount. Corresponding to the temperature around the X-ray conversion layer 23, the dark signal at that temperature is read out, and the dark signal amount and the temperature around the X-ray conversion layer 23 when the dark signal amount is obtained are correlated. And plot. When the plotted graph is approximated by, for example, the method of least squares, the correlation between the dark signal amount (in this case, the conversion layer leakage component) and the temperature around the X-ray conversion layer 23 is expressed by the following equation (1). It is expressed in

I = α {exp (β / T) −1} (1)
However, I is a dark signal amount (conversion layer leak component), α and β are constants, and T is a temperature [K]. Exp is an exponential function. The constants α and β correspond to the coefficients used in the approximate expression in the present invention.

  In general, the temperature of the environment in which the apparatus is used is constantly changing, and a clinical diagnosis problem arises when a temperature change of the dark signal amount appears in an image. Therefore, an approximate expression of the expression (1) as described above is obtained, the actual temperature is measured by the temperature sensor 10, and the measured temperature around the X-ray conversion layer 23 is substituted into the expression (1). Thus, the actual dark signal amount is obtained, and the dark signal amount is subtracted from the irradiation carrier to correct the irradiation carrier.

  The correlation memory unit 7a stores the above correlation in advance. The approximate expression of the above equation (1) relating to the dark signal amount and the in-plane distribution information regarding the temperature around the X-ray conversion layer 23 when the dark signal amount is obtained is programmed, and the program is stored in the correlation memory unit 7a. To remember. When the actual temperature is measured by the temperature sensor 10, the program is read from the correlation memory unit 7 a of the memory unit 7, and the program is executed by the controller 6, so that the periphery of the measured X-ray conversion layer 23 is measured. A control sequence for correcting the carrier at the time of irradiation is performed by substituting the temperature into the equation (1) to obtain the actual dark signal amount and subtracting the dark signal amount from the carrier at the time of irradiation. Further, a table in which the dark signal amount and the in-plane distribution information regarding the temperature around the X-ray conversion layer 23 when the dark signal amount is obtained may be stored in the correlation memory unit 7a in advance.

  The actual temperature is distributed in the plane, and there is variation at each location. Therefore, as described above, the temperature sensors 10 are provided at the four corners of the base plate 41 outside the effective detection area A, and the temperature sensors 10 are also provided at the central region in the effective detection area A, so that the four corners and the central region are respectively provided. In-plane distribution information relating to the temperature around the X-ray conversion layer 23 is obtained by acquiring the temperature in each corresponding pixel region. For in-plane distribution information, it is most preferable to obtain in-plane distribution information by measuring the temperature for each pixel. However, a plurality of pixels that are close to each other are collected as one pixel area, and the temperature is determined for each pixel area. The in-plane distribution information may be acquired by measuring. If temperature interpolation is performed as described later, it is not necessary to measure the temperature for every pixel region. For example, the temperature sensors 10 are provided at the four corners of the base plate 41 outside the effective detection area A as described above. The temperature sensor 10 may be provided only in the central region within the effective detection area A.

The constants α and β used in the above equation (1) are not uniform within the surface as with the temperature, and there are variations at each location. Accordingly, the constants α and β satisfying the above equation (1) are obtained by associating the dark signal read in advance for each pixel region with the temperature measured corresponding to the pixel region. For each pixel area. Thus, by determining the constants α and β for each pixel region, a table of in-plane distribution information relating to coefficients (here, constants α and β) used in the approximate expression (here, the above expression (1)) is obtained. 6 (see (α ₁ , β ₁ ) and (α _N , β _N ) in FIG. 6). This table of in-plane distribution information is stored in advance in the coefficient in-plane distribution information memory unit 7b.

As for temperature interpolation, when the above correlation is stored in advance, the actual temperature is measured, the actual dark signal amount is obtained, and the dark signal amount is subtracted from the carrier at the time of irradiation. It is also performed when correcting the carrier during irradiation. For example, the temperatures measured by the temperature sensors 10 provided at the four corners of the base plate 41 outside the effective detection area A are T ₁ , T ₂ , T ₃ and T ₄ as shown in FIG. the temperature measured by the temperature sensor 10 provided in a central region of the inner, and T ₅ as shown in FIG. 7, when the temperature at the point (pixel region) in which the temperature sensor 10 is not provided to the T _X in interpolates the temperature _{T X} using the temperature _{T 1, T 2, T 3} , T 4 and _{T 5} in places where the temperature sensor 10 is provided (four corners and the central region in example 1). Interpolation is not particularly limited as exemplified by linear interpolation.

  When the above correlation is stored in advance, the temperatures in the respective pixel regions respectively corresponding to the four corners and the central region are acquired, and in-plane distribution information regarding the temperature around the X-ray conversion layer 23 is obtained. Thus, by performing temperature interpolation as shown in FIG. 7, in-plane distribution information regarding the temperature around the X-ray conversion layer 23 for every pixel region is obtained. The constants α and β satisfying the above equation (1) are obtained by associating the dark signal read in advance for each pixel area with the temperature measured or interpolated corresponding to the pixel area. A table of in-plane distribution information relating to coefficients (here, constants α, β) as shown in FIG. 6 is obtained for each pixel area.

  When measuring the actual temperature, obtaining the actual dark signal amount, and subtracting the dark signal amount from the carrier at the time of irradiation to correct the carrier at the time of irradiation, the four corners and the central region are respectively The temperature in each corresponding pixel region is acquired, the in-plane distribution information regarding the temperature around the X-ray conversion layer 23 is obtained, and the temperature interpolation is performed as shown in FIG. In-plane distribution information relating to the temperature around the line conversion layer 23 is obtained. By substituting the temperature around the X-ray conversion layer 23 measured or interpolated for each pixel area into the above equation (1) for each pixel area obtained from the in-plane distribution information table, The actual dark signal amount for each pixel region is obtained, and the dark signal amount is subtracted from the carrier at the time of irradiation to correct the carrier at the time of irradiation for each pixel region.

  According to the X-ray imaging apparatus according to the first embodiment described above, the temperature sensor 10 other than the X-ray conversion layer 23 is used by using the temperature around the X-ray conversion layer 23 instead of the temperature of the X-ray conversion layer 23. (In the first embodiment, the base plate 41) can be easily disposed. Further, the temperature around the X-ray conversion layer 23 is measured in a plurality of areas within a predetermined plane around the X-ray conversion layer 23 (the base plate 41 in the first embodiment), and the temperature around the X-ray conversion layer 23 is related. Since the temperature sensor 10 obtains the in-plane distribution information, the temperature can be accurately obtained even in a region (pixel region) away from the location where the temperature sensor 10 is provided. Therefore, the correlation between the dark signal amount and the in-plane distribution information regarding the temperature around the X-ray conversion layer 23 when the dark signal amount is obtained, and the temperature around the X-ray conversion layer 23 measured by the temperature sensor 10. Based on the in-plane distribution information regarding the dark signal amount, the dark signal amount calculation function can accurately determine the dark signal amount. In summary, the temperature sensor 10 can be easily disposed, and the dark signal amount can be accurately obtained and imaging can be performed.

  A specific effect capable of easily disposing the temperature sensor 10 will be described. For example, by using the temperature around the X-ray conversion layer 23 where the temperature sensor 10 can be easily installed, the cost of disposing the temperature sensor 10 for embedding the temperature sensor 10 can be reduced.

  In the first embodiment, the above correlation is stored in advance in the correlation memory unit 7a. The correlation may be a table in which the dark signal amount and the in-plane distribution information related to the temperature around the X-ray conversion layer 23 when the dark signal amount is obtained as described above, An approximate expression (the expression (1) in the first embodiment) relating to the dark signal amount and the in-plane distribution information related to the temperature around the X-ray conversion layer 23 when the dark signal amount is obtained may be programmed.

In the first embodiment, preferably, the temperature (here, T _X ) at the location where the temperature sensor 10 is not provided is changed to the temperature (here, the four corners or the central region) where the temperature sensor 10 is provided (here, the center region). _{T 1, T 2, T 3} , T function of temperature interpolation using ₄ and _{T 5)} is interpolated. The temperature can be accurately obtained by interpolating the temperature by the function of temperature interpolation while reducing the number of temperature sensors to be provided in the plane.

  In the first embodiment, preferably, the above-described correlation is an approximate expression (the expression (1) in the first embodiment) regarding the dark signal amount and the in-plane distribution information regarding the temperature around the X-ray conversion layer 23. In addition, a coefficient in-plane distribution information memory unit 7b that stores in-plane distribution information related to the coefficients (constants α and β in the first embodiment) used in the approximate expression is provided. The coefficients (constants α, β) used in the approximate expression are not uniform in the plane and vary in the plane. Therefore, the characteristics of the approximate expression also vary within the plane. Therefore, by providing the coefficient in-plane distribution information memory unit 7b for storing the in-plane distribution information regarding the coefficients (constants α, β), the dark signal amount can be more accurately obtained even if the characteristics of the approximate expression vary in the plane. Can be requested. In the first embodiment, as shown in FIG. 6, each location (pixel region) in the plane is associated with coefficients (constants α, β) at the location (pixel region).

  In the first embodiment, the temperature sensor 10 is disposed on a structure (base plate 41 in the first embodiment) provided on the opposite side of the X-ray conversion layer 23 from the X-ray incident side. When the temperature sensor 10 is disposed on the structure (base plate 41) provided on the side opposite to the incident side as in the first embodiment, the temperature sensor 10 does not hinder the incidence of X-rays. The temperature sensor 10 can be provided at any location. Therefore, the temperature sensor 10 may be arranged also in the X-ray detection effective area A (in the case of FIG. 5, the central area of the detection effective area A) of the structure (base plate 41). By arranging the temperature sensor 10 in the effective detection area A as described above, the temperature in the effective detection area A can be accurately obtained, and the dark signal amount in the effective detection area A can be accurately obtained. .

  An example of the arrangement of the temperature sensor 10 when viewed from the incident is as described above, but an example of the arrangement of the temperature sensor 10 when viewed from a specific structure other than the incident is as follows.

  That is, in the first embodiment, the base plate 41 that holds the X-ray conversion layer 23 and the detection element circuit 2 is provided, and the temperature sensor 10 is disposed on the base plate 41. Usually, since the holding member represented by the base plate 41 is often provided on the opposite side to the incident side, the temperature sensor 10 can be disposed also in the detection effective area A of the base plate 41. Of course, the present invention can also be applied to the case where light or radiation (X-rays in the first embodiment) is incident from the holding member represented by the base plate 41.

Next, Embodiment 2 of the present invention will be described with reference to the drawings.
FIG. 8 is a schematic cross-sectional view of a structure in which the X-ray conversion layer, the detection element circuit, and the like of the X-ray imaging apparatus according to Embodiment 2 are mold-sealed. About the same structure as Example 1 mentioned above, the same code | symbol is attached | subjected and the description is abbreviate | omitted.

  The X-ray imaging apparatus according to the second embodiment has a gate drive circuit 1, a detection element circuit 2, a charge-voltage conversion amplifier 3, an A / D converter 4, and an image processing unit 5 as in the first embodiment. A controller 6, a memory unit 7, an input unit 8, and a monitor 9.

  In the second embodiment, as in the first embodiment described above, the place where the temperature sensor 10 serving as the temperature measuring means is disposed is a structure provided on the side opposite to the incident side. However, unlike Example 1 described above, Example 2 employs an insulating substrate 21 as its structure. Therefore, the temperature sensor 10 is provided on the insulating substrate 21. In order to obtain in-plane distribution information relating to the temperature around the X-ray conversion layer 23, a plurality of temperature sensors 10 are provided. As shown in FIG. 8, in Example 2, the temperature sensors 10 are provided at the four corners of the insulating substrate 21 near the end of the X-ray conversion layer 23 outside the effective detection area A (only two corners are shown in FIG. 8). The temperature sensor 10 is also provided in the central region in the effective detection area A.

  Since a series of control sequences is the same as that in the first embodiment, the description thereof is omitted.

  According to the X-ray imaging apparatus according to the second embodiment described above, a plurality of temperatures around the X-ray conversion layer 23 can be obtained within a predetermined plane around the X-ray conversion layer 23 (the insulating substrate 21 in the second embodiment). Since the temperature sensor 10 obtains in-plane distribution information regarding the temperature around the X-ray conversion layer 23, the temperature can be accurately obtained even in a region (pixel region) away from the location where the temperature sensor 10 is provided. The correlation between the dark signal amount and the in-plane distribution information regarding the temperature around the X-ray conversion layer 23 when the dark signal amount is obtained, and the vicinity of the X-ray conversion layer 23 measured by the temperature sensor 10 Based on the in-plane distribution information related to temperature, the dark signal amount calculation function can accurately determine the dark signal amount. As a result, similarly to the above-described first embodiment, the temperature sensor 10 can be easily disposed, and the dark signal amount can be accurately obtained and imaging can be performed.

  In the second embodiment, the temperature sensor 10 is disposed on a structure (insulating substrate 21 in the second embodiment) provided on the opposite side of the X-ray conversion layer 23 from the X-ray incident side. When the temperature sensor 10 is disposed on the structure (insulating substrate 21) provided on the side opposite to the incident side as in the second embodiment, the temperature sensor 10 is provided as in the first embodiment. Since it does not interfere with the incidence of X-rays, the temperature sensor 10 can be provided at an arbitrary location. Therefore, the temperature sensor 10 may be arranged also in the X-ray detection effective area A (in the case of FIG. 8, the central region of the detection effective area A) of the structure (insulating substrate 21). By arranging the temperature sensor 10 in the effective detection area A as described above, the temperature in the effective detection area A can be accurately obtained, and the dark signal amount in the effective detection area A can be accurately obtained. .

  In the second embodiment, an insulating substrate 21 for patterning the detection element circuit 2 is provided, and the temperature sensor 10 is disposed on the insulating substrate 21. Of course, in combination with the base plate 41 of the first embodiment, the temperature sensor 10 may be disposed on the base plate 41 and the temperature sensor 10 may be disposed on the insulating substrate 21.

Next, Embodiment 3 of the present invention will be described with reference to the drawings.
FIG. 9 is a schematic cross-sectional view of a structure in which an X-ray conversion layer, a detection element circuit, and the like of the X-ray imaging apparatus according to Embodiment 3 are molded and sealed. The same components as those in the first and second embodiments are denoted by the same reference numerals and description thereof is omitted.

  As in the first and second embodiments, the X-ray imaging apparatus according to the third embodiment includes a gate drive circuit 1, a detection element circuit 2, a charge-voltage conversion amplifier 3, an A / D converter 4, and image processing. A unit 5, a controller 6, a memory unit 7, an input unit 8, and a monitor 9 are provided.

  Unlike the first and second embodiments described above, in the third embodiment, a place where the temperature sensor 10 serving as a temperature measuring unit is disposed is a structure provided on the incident side. In the third embodiment, the voltage application electrode 24 is employed as the structure. Therefore, the temperature sensor 10 is provided on the voltage application electrode 24. In order to obtain in-plane distribution information relating to the temperature around the X-ray conversion layer 23, a plurality of temperature sensors 10 are provided. As shown in FIG. 9, in Example 3, the temperature sensors 10 are provided at the four corners of the voltage application electrode 24 near the end of the X-ray conversion layer 23 outside the effective detection area A (only two corners are shown in FIG. 9). .

  Note that a series of control sequences is the same as those in the first and second embodiments, and a description thereof will be omitted.

  According to the X-ray imaging apparatus according to the third embodiment described above, the temperature around the X-ray conversion layer 23 is changed within a predetermined plane around the X-ray conversion layer 23 (the voltage application electrode 24 in the third embodiment). Since the temperature sensor 10 obtains in-plane distribution information relating to the temperature around the X-ray conversion layer 23 by measuring a plurality of temperatures, the temperature is accurately obtained even in a region (pixel region) away from the location where the temperature sensor 10 is provided. The correlation between the dark signal amount and the in-plane distribution information regarding the temperature around the X-ray conversion layer 23 when the dark signal amount is obtained, and the periphery of the X-ray conversion layer 23 measured by the temperature sensor 10 Based on the in-plane distribution information regarding the temperature, the dark signal amount calculation function can accurately determine the dark signal amount. As a result, similar to the first and second embodiments described above, the temperature sensor 10 can be easily disposed, and the dark signal amount can be accurately obtained and imaging can be performed.

  In the third embodiment, the temperature sensor 10 is disposed on a structure (the voltage application electrode 24 in the third embodiment) provided on the X-ray incident side of the X-ray conversion layer 23. Of course, as in the first and second embodiments described above, the temperature sensor 10 is disposed on a structure (the base plate 41 in the first embodiment and the insulating substrate 21 in the second embodiment) provided on the side opposite to the incident side. In addition, as in the third embodiment, a structure provided on the light incident side of the conversion layer (X-ray conversion layer 23 in each of the first to third embodiments) or radiation (X-ray in each of the first to third embodiments). The temperature sensor 10 may be disposed on the voltage application electrode 24 (in the third embodiment), and the first and second embodiments may be combined with the third embodiment.

  In the third embodiment, a voltage application electrode 24 for applying a bias voltage is provided, and the temperature sensor 10 is disposed on the voltage application electrode 24. Of course, the temperature sensor 10 is disposed on the base plate 41 or the insulating substrate 21 in combination with the base plate 41 of the first embodiment or the insulating substrate 21 of the second embodiment, and the temperature sensor 10 is disposed on the voltage application electrode 24. You may set up. The temperature sensors 10 may be disposed on all of the base plate 41, the insulating substrate 21, and the voltage application electrode 24, respectively.

Next, a fourth embodiment of the present invention will be described with reference to the drawings.
FIG. 10 is a schematic cross-sectional view of a structure in which an X-ray conversion layer, a detection element circuit, and the like of the X-ray imaging apparatus according to Embodiment 4 are molded and sealed. About the same structure as Examples 1-3 mentioned above, the same code | symbol is attached | subjected and the description is abbreviate | omitted.

  In the X-ray imaging apparatus according to the fourth embodiment, the gate drive circuit 1, the detection element circuit 2, the charge-voltage conversion amplifier 3, the A / D converter 4, and the image processing are performed as in the first to third embodiments. A unit 5, a controller 6, a memory unit 7, an input unit 8, and a monitor 9 are provided.

  Unlike the first and second embodiments described above, in the fourth embodiment, as in the third embodiment described above, a structure in which the temperature sensor 10 serving as a temperature measuring unit is provided on the incident side. It is a thing. In the fourth embodiment, a resin film 44 is employed as the structure. Therefore, the temperature sensor 10 is provided on the resin film 44. In order to obtain in-plane distribution information relating to the temperature around the X-ray conversion layer 23, a plurality of temperature sensors 10 are provided. As shown in FIG. 10, in Example 4, the temperature sensors 10 are provided at the four corners of the resin film 44 near the end of the X-ray conversion layer 23 outside the effective detection area A (only two corners are shown in FIG. 10).

  In addition, about a series of control sequences, since it is the same as Examples 1-3 mentioned above, the description is abbreviate | omitted.

  According to the X-ray imaging apparatus according to the fourth embodiment described above, a plurality of temperatures around the X-ray conversion layer 23 are set in a predetermined plane around the X-ray conversion layer 23 (resin film 44 in the fourth embodiment). Since the temperature sensor 10 obtains in-plane distribution information regarding the temperature around the X-ray conversion layer 23, the temperature can be accurately obtained even in a region (pixel region) away from the location where the temperature sensor 10 is provided. The correlation between the dark signal amount and the in-plane distribution information regarding the temperature around the X-ray conversion layer 23 when the dark signal amount is obtained, and the vicinity of the X-ray conversion layer 23 measured by the temperature sensor 10 Based on the in-plane distribution information related to temperature, the dark signal amount calculation function can accurately determine the dark signal amount. As a result, similarly to the first to third embodiments described above, the temperature sensor 10 can be easily disposed, and the dark signal amount can be accurately obtained and imaging can be performed.

  In the fourth embodiment, the temperature sensor 10 is disposed on a structure (resin film 44 in the fourth embodiment) provided on the X-ray incident side of the X-ray conversion layer 23. Of course, as in the first and second embodiments described above, the temperature sensor 10 is disposed on a structure (the base plate 41 in the first embodiment and the insulating substrate 21 in the second embodiment) provided on the side opposite to the incident side. In addition, as in Example 3 and Example 4 described above, the incident side of light or radiation (X-rays in Examples 1 to 4) of the conversion layer (X-ray conversion layer 23 in Examples 1 to 4). The temperature sensor 10 is disposed on the structure (the voltage application electrode 24 in the third embodiment and the resin film 44 in the fourth embodiment) provided in the first, second, third, fourth, and fourth embodiments. May be combined.

  In the fourth embodiment, the X-ray conversion layer 23 and the detection element circuit 2 are sealed with a resin film 44 that is an insulator, and the temperature sensor 10 is disposed on the sealed resin film 44. Of course, the temperature sensor 10 is arranged on the base plate 41, the insulating substrate 21 or the voltage applying electrode 24 in combination with the base plate 41 of the first embodiment, the insulating substrate 21 of the second embodiment, or the voltage applying electrode 24 of the third embodiment. In addition, the temperature sensor 10 may be disposed on the resin film 44. The temperature sensors 10 may be disposed on all of the base plate 41, the insulating substrate 21, the voltage application electrode 24, and the resin film 44, respectively.

  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 imaging apparatus as shown in FIG. 1 has been described as an example. However, the present invention is also applicable to an X-ray fluoroscopic imaging apparatus disposed on a C-type arm, for example. May be. The present invention may also be applied to an X-ray CT apparatus.

  (2) In each of the embodiments described above, a “direct conversion type” detection element circuit in which radiation represented by incident X-rays is directly converted into charge information by an X-ray conversion layer (conversion layer) is provided in the present invention. Applied, but the incident radiation is converted into light by a conversion layer such as a scintillator, and the light is converted into charge information by a conversion layer formed of a photosensitive material. The present invention may be applied.

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

  (4) In each of the embodiments described above, radiation imaging typified by X-rays and the like has been described as an example, but the present invention can also be applied to an apparatus that performs imaging by the incidence of light.

  (5) In each of the embodiments described above, the voltage application electrode 24 has a structure as shown in FIG. 2 or FIG. 4, but for example, a structure having a graphite substrate that also serves as a support substrate and a voltage application electrode. The invention can be applied. In this case, a temperature sensor can be disposed on the graphite substrate as in the third embodiment. Moreover, it is not limited to the structure for mold sealing as shown in FIG.

  (6) As in the above-described embodiments, the location of the temperature sensor 10 is not limited to the base plate 41, the insulating substrate 21, the voltage application electrode 24, and the resin film 44. If the temperature near the conversion layer (X-ray conversion layer 23 in each embodiment) and the temperature near the conversion layer or the temperature of the conversion layer can be estimated, the location of the temperature sensor 10 may be another location.

  (7) In each of the above-described embodiments, the temperature interpolation is performed, but the temperature interpolation is not necessarily performed.

DESCRIPTION OF SYMBOLS 10 ... Temperature sensor 2 ... Detection element circuit 21 ... Insulating substrate 23 ... X-ray conversion layer 24 ... Voltage application electrode 41 ... Base board 44 ... Resin film 6 ... Controller 7a ... Correlation memory part 7b ... Coefficient in-plane distribution information memory Part I ... Dark signal amount (conversion layer leak component)
T ... Temperature α, β ... Constant

Claims (11)

A conversion layer that converts light or radiation information into charge information by the incidence of light or radiation; and
A storage / readout circuit that stores and reads out the charge information converted by the conversion layer,
An imaging device that obtains an image based on charge information read by the storage / readout circuit,
A temperature measuring means for measuring a plurality of temperatures around the conversion layer within a predetermined plane around the conversion layer, and obtaining in-plane distribution information relating to the temperature around the conversion layer;
Correlation between the dark signal amount equivalent to the charge when not irradiated with light or radiation and the in-plane distribution information regarding the temperature around the conversion layer when the dark signal amount was obtained, and measured by the temperature measuring means Dark signal amount calculating means for obtaining the dark signal amount based on in-plane distribution information relating to the temperature around the conversion layer;
An image pickup apparatus comprising: a correction unit that corrects charge information at the time of irradiation based on the dark signal amount obtained by the dark signal amount calculation unit. The imaging device according to claim 1,
An imaging apparatus comprising correlation storage means for storing the correlation in advance. In the imaging device according to claim 1 or 2,
An imaging apparatus comprising temperature interpolation means for interpolating a temperature at a location where the temperature measurement means is not provided using a temperature at a location where the temperature measurement means is provided. In the imaging device in any one of Claims 1-3,
The correlation is an approximate expression related to the dark signal amount and in-plane distribution information related to the temperature around the conversion layer,
An image pickup apparatus comprising coefficient in-plane distribution information storage means for storing in-plane distribution information relating to a coefficient used in the approximate expression. In the imaging device according to any one of claims 1 to 4,
An image pickup apparatus, wherein the temperature measuring means is disposed on a structure provided on a side opposite to the light or radiation incident side of the conversion layer. The imaging apparatus according to claim 5,
An image pickup apparatus, wherein the temperature measuring means is also disposed in the effective detection area of the light or radiation of the structure. The imaging apparatus according to any one of claims 1 to 6,
An image pickup apparatus, wherein the temperature measuring means is disposed on a structure provided on the light or radiation incident side of the conversion layer. In the imaging device in any one of Claims 1-7,
A holding member for holding the conversion layer and the storage / readout circuit;
An image pickup apparatus, wherein the temperature measuring means is disposed on the holding member. In the imaging device in any one of Claims 1-8,
A substrate for patterning the storage / readout circuit;
An image pickup apparatus, wherein the temperature measuring means is disposed on the substrate. In the imaging device in any one of Claims 1-9,
A voltage application electrode for applying a bias voltage;
An image pickup apparatus, wherein the temperature measuring means is disposed on the voltage application electrode. In the imaging device in any one of Claims 1-10,
Sealing the conversion layer and the storage / readout circuit with an insulator;
An image pickup apparatus, wherein the temperature measuring means is disposed on the sealed insulator.

Images