JPWO2013038815A1 - Image sensor and radiographic imaging device - Google Patents

Abstract

In an image sensor in which a plurality of conversion units are two-dimensionally arranged, an image sensor using a conversion unit including a switch element with a simplified structure is provided. The image sensor 1 is electrically connected to a plurality of conversion units 5 including a first electrode 5 a and a second electrode 5 b arranged in a two-dimensional manner on a substrate 4, and the first electrodes 5 a of each conversion unit 5. Each resistance switch 6 provided to be connected, each signal line 7 wired to be connected to each resistance switch 6, and wired to be connected to the second electrode 5 b of each conversion unit 5 Each conversion is performed by controlling the operation of each bias line 8, each switching driver 10 connected to each bias line 8, each readout circuit 14 connected to each signal line 7, and each switching driver 10 and each readout circuit 14. And a control unit 20 that performs a process of reading image data from the unit 5.

Description

  The present invention relates to an image sensor and a radiographic imaging apparatus, and more particularly to an image sensor in which a plurality of conversion units are arranged in a two-dimensional manner and a radiographic imaging apparatus using the same.

  2. Description of the Related Art An image sensor that captures an image by generating electric charges according to the amount of light such as visible light irradiated by a conversion unit arranged in a two-dimensional form (matrix form) and converting the electric signal into an electric signal is known. . In addition, as an apparatus using such an image sensor, for example, after converting irradiated radiation such as X-rays into light of other wavelengths such as visible light with a scintillator or the like, it is converted into energy of the irradiated light. In response to this, various radiographic imaging apparatuses have been developed that generate charges in a converter such as a photodiode and convert them into electrical signals (that is, image data).

  This type of radiographic imaging device is known as an FPD (Flat Panel Detector), and is conventionally configured as a so-called special-purpose machine that is integrally formed with a support base (see, for example, Patent Document 1). In recent years, portable radiographic image capturing apparatuses that can accommodate two-dimensionally arranged conversion units in a housing and are portable have been developed and put into practical use (for example, see Patent Documents 2 and 3).

  In such an image sensor (or radiographic image capturing apparatus; the same applies hereinafter), for example, as shown in FIG. 17, usually, a plurality of conversion units A are two-dimensionally arranged on a substrate, and one of the conversion units A is arranged. The signal line Si is connected to the electrode Aa on the side through a thin film transistor (hereinafter referred to as TFT) which is a switch element.

  In order to control the opening and closing of the TFT, the scanning line Ga to which a voltage for turning on / off the TFT is normally connected to the gate electrode G of each TFT. Note that S and D in FIG. 17 represent a source electrode and a drain electrode of the TFT, respectively.

  The bias line B is connected to the electrode Ab on the other side of each conversion unit A. A bias voltage is applied to each conversion unit A from the bias power supply Pb via the bias line B. In a normal state, a bias voltage in a direction in which no current flows in each converter A, that is, a so-called reverse bias voltage, is applied instead of a direction in which current flows in each converter A.

  In this state, when each TFT is turned off and the image sensor is irradiated with light, electrons and holes generated in each conversion portion A due to light irradiation are converted without recombination. It moves to the corresponding electrode Aa, Ab side of the part A.

  That is, the generated holes move to the electrode having the lower potential (ie, the electrode Ab to which the bias line B is connected), and the generated electrons are signaled via the electrode having the higher potential (ie, the TFT, for example). It moves to the electrode Aa) side connected to the line Si. In this manner, in each converter A, by applying a reverse bias voltage, electrons and holes generated by light irradiation move to the corresponding electrodes Aa and Ab, respectively, and are separated.

  In this state, an ON voltage is applied to the gate electrode G of the TFT, so that electrons (or holes, hereinafter collectively referred to as charges) are emitted from the conversion portion A to the signal line Si. Then, the electric charge flows through the signal line Si and flows into the readout circuit Cro, and is converted into image data by the readout circuit Cro. In this way, the image data corresponding to the electric charges generated in each conversion unit A due to the irradiation of radiation is configured to be read out.

JP-A-9-73144 JP 2006-058124 A JP-A-6-342099

  By the way, as a result of repeated studies by the present inventors on the configuration of the image sensor and the radiographic imaging device, the configuration of the conversion unit, etc., it has been found that the conversion unit can be configured with a simpler structure. It was. More specifically, it has been found that the switch element of the conversion unit can be configured with a simpler structure rather than a switch element having a complicated configuration such as the above-described TFT.

  Then, by adopting such a simple configuration for the switching element of the conversion unit, a voltage for turning on / off the TFT gate, which has been used in the above-described conventional image sensor and radiographic apparatus, is applied. It has also been found that various beneficial effects can be obtained, such as eliminating the need for the scanning line Ga, and making it possible to more easily produce the conversion unit, the image sensor, and the radiation image capturing apparatus.

  The present invention has been made in view of the above problems, and in an image sensor in which a plurality of conversion units are arranged two-dimensionally, an image using a conversion unit including a switch element with a more simplified structure. It is an object of the present invention to provide a sensor and to provide a radiographic image capturing apparatus using the sensor.

In order to solve the above-described problem, the image sensor of the present invention includes:
A plurality of converters including a first electrode and a second electrode, two-dimensionally arranged on the substrate;
Each resistance switch that is provided so as to be electrically connected to the first electrode of each of the conversion units, and whose resistance value changes by voltage application;
Each signal line wired so as to be connected to each of the resistance switches for each column of the conversion units arranged two-dimensionally,
For each row of each of the converters arranged in a two-dimensional manner, each bias line wired to be connected to the second electrode of each converter, and applying a voltage to each converter,
A switching driver for switching the voltage value of the voltage applied to each bias line;
Each readout circuit provided for each of the signal lines, which converts the charges discharged from the conversion unit to the corresponding signal lines into image data and reads out the image data;
Control means for controlling the operation of at least the switching driver and each readout circuit to read out the image data from the respective conversion units to read out the electric charges generated in the respective conversion units by the light irradiation as the image data. When,
It is characterized by providing.

Moreover, the radiographic imaging device of the present invention is
The image sensor of the present invention,
When irradiated with radiation, a scintillator that converts the radiation into light and outputs the light to each conversion unit;
It is characterized by providing.

  According to the image sensor and the radiographic imaging apparatus of the system of the present invention, since the resistance switch is used as the switch element of each conversion unit, for example, as shown in FIG. It becomes possible to further simplify.

  In addition, when the resistance switch is used as the switching element of each conversion unit in this way, the on / off operation of the resistance switch, that is, the transition between the high resistance state and the low resistance state is performed via the bias line. Thus, it is possible to change the voltage applied to each converter. Further, for example, since a TFT is not used as a switching element as in the conventional conversion unit A shown in FIG. 17, a scanning line for applying a voltage for turning on / off the TFT to an image sensor or a radiographic imaging device. There is no need to provide Ga.

  In addition, since the scanning line Ga is not provided, a beneficial effect such as an increase in the degree of freedom of layout of the conversion unit, the resistance switch, the signal line, the bias line, etc. on the substrate of the image sensor or the radiographic imaging apparatus is obtained. It is done. Further, it has been necessary to repeatedly perform a complicated process for forming a TFT, but the resistance switch can be performed by a simpler method using a shadow mask, for example.

  Therefore, the conversion unit can be manufactured by a simple manufacturing process, and the conversion unit, the image sensor, and the radiographic imaging device can be manufactured by a simpler production process. For this reason, it is possible to improve the productivity of the conversion unit, the image sensor, and the radiation image capturing apparatus, and it is also possible to obtain a beneficial effect that the yield in production can be improved. .

It is a perspective view which shows the external appearance of the radiographic imaging apparatus which concerns on this embodiment. It is sectional drawing which follows the XX line in FIG. It is a perspective view showing the state which connected the connector of the cable to the connector of the radiographic imaging apparatus. It is a block diagram showing the equivalent circuit of the image sensor which concerns on this embodiment. It is an enlarged view of the conversion part of the image sensor which concerns on this embodiment. It is sectional drawing which follows the YY line in FIG. It is a flowchart showing each process in the manufacturing process of the conversion part containing a resistance switch. It is a figure showing the state by which the signal line is arrange | positioned on the board | substrate in the manufacturing process of the conversion part. It is a figure showing the state by which the electrode was laminated | stacked on the board | substrate and the signal wire | line in the manufacturing process of a conversion part. It is a figure showing the electrode etc. in which the recessed part was provided. It is a figure showing the electrode etc. which were formed in the rectangular shape. It is a figure explaining that a resistance switch may produce step breakage by the edge part where the electrode stood. It is a figure explaining that when a mask material is laminated on the base part formed so that an electrode may be surrounded, it will be in the state where a sputtered molecule goes into the crevice between an electrode and a mask material. It is a figure showing the main-body part, 2nd electrode, etc. of the conversion part of the state coat | covered with the insulating layer. When the applied voltage V exceeds a certain threshold value with a positive voltage, it switches from a low resistance state to a high resistance state, and when it exceeds a certain threshold value with a negative voltage, it switches from a high resistance state to a low resistance state. It is a graph explaining an example of a bipolar resistance switch. It is a graph showing time transitions, such as voltage Vb applied to the 2nd electrode of a conversion part, and voltage V applied between the electrode of a resistance switch, and the 1st electrode, when a bipolar type resistance switch is used. The relationship between the potential V between the first electrode and the second electrode and the flowing current I in a unipolar resistance switch of a type in which a high resistance state and a low resistance state are switched when the applied voltage V exceeds a threshold value will be described. It is a graph. It is a graph showing time transitions, such as voltage Vb applied to the 2nd electrode of a conversion part, and voltage V applied between the electrode of a resistance switch, and the 1st electrode, when a unipolar type resistance switch is used. It is a block diagram showing the example of the equivalent circuit of the conventional radiographic imaging apparatus which used TFT as a switch element of a conversion part.

  Embodiments of an image sensor and a radiographic imaging apparatus according to the present invention will be described below with reference to the drawings.

  In the following, a configuration example in which an image sensor is applied to a radiographic imaging device will be described. However, for example, the image sensor may be configured to be used as an image sensor for other imaging devices such as a digital camera. It is possible, and the present invention is also applied to such a configuration.

  In the following, a so-called portable radiographic imaging apparatus will be described as the radiographic imaging apparatus. However, for example, a radiographic imaging of a dedicated machine type (also referred to as a fixed type) integrally formed with a support base or the like. The present invention can be applied to an apparatus.

[Configuration as a radiographic imaging device]
Hereinafter, a configuration as a radiographic imaging device will be described first. FIG. 1 is a perspective view showing an external appearance of the radiographic image capturing apparatus according to the present embodiment, and FIG. 2 is a cross-sectional view taken along line XX of FIG. As shown in FIGS. 1 and 2, the radiation image capturing apparatus 100 includes a housing 2 in which a sensor panel SP including a scintillator 3 and a substrate 4 is accommodated.

  In the following description, the up and down direction is represented in accordance with the up and down direction in FIGS. 1 and 2 (that is, the upper side in the drawing is represented as “upper”, “upward”, etc.).

  In the present embodiment, the housing 2 is formed of a material such as a carbon plate or plastic, and the openings on both sides of the housing main body 2A having the radiation incident surface R are closed by the lid members 2B and 2C. ing. Further, the lid member 2B on one side of the housing 2 has a power switch 37, a changeover switch 38, a connector 39, an indicator 40 composed of an LED or the like for displaying a battery state, an operating state of the radiographic imaging apparatus 1, and the like. Is arranged.

  In the present embodiment, for example, as shown in FIG. 3, a connector C provided at the tip of the cable Ca is connected to the connector 39, so that signals and data are transmitted / received to / from an external device via the cable Ca. It can be done. Although not shown, in the present embodiment, an antenna device 41 (see FIG. 4 described later) is provided on the lid member 2C on the opposite side of the housing 2, and an external device is connected via the antenna device 41. It is also possible to transmit and receive signals and data in a wireless manner.

  As shown in FIG. 2, a base 31 is disposed inside the housing 2 via a lead thin plate (not shown) on the lower side of the substrate 4, and an electronic component 32 and the like are disposed on the base 31. The PCB substrate 33, the battery 22 and the like are attached. Further, a glass substrate 34 for protecting the substrate 4 and the radiation incident surface R of the scintillator 3 is disposed. In the present embodiment, the buffer material 35 is provided between the sensor panel SP and the side surface of the housing 2.

  The scintillator 3 is provided at a position on the substrate 4 that faces a detection unit P described later. In this embodiment, the scintillator 3 is, for example, a phosphor whose main component is converted into light having a wavelength of 300 to 800 nm, that is, an electromagnetic wave centered on visible light and output when receiving radiation. .

  Moreover, in this embodiment, the board | substrate 4 is comprised with the glass substrate, and on the surface 4a of the side facing the scintillator 3 of the board | substrate 4, the several conversion part 5 mentioned later, the several signal wire | line 7, and several Bias line 8 and the like are provided.

[Image sensor configuration]
Hereinafter, the circuit configuration of the image sensor 1 will be described. FIG. 4 is a block diagram showing an equivalent circuit of the image sensor 1 according to the present embodiment. In FIG. 4, an antenna device 41 used in the radiographic image capturing apparatus 100 and a correlated double sampling circuit 16 (described as “CDS” in the drawing), which will be described later, are also shown.

  On the substrate 4 (see FIG. 2) of the image sensor 1, as shown in FIG. 4, a plurality of converters 5 are arranged two-dimensionally (matrix). In the present embodiment, the conversion unit 5 has a radiation incident from a radiation incident surface R (see FIG. 1 and the like) of the housing 2 of the radiographic imaging device 100, and is converted into visible light from the scintillator 3 (see FIG. 2). When light such as light is irradiated, electron-hole pairs are generated in an i layer 5e described later (see FIG. 6 described later).

  In this way, the converter 5 converts the irradiated radiation (in this embodiment, light converted from the radiation by the scintillator 3) into electric charges. A region in which the plurality of conversion units 5 are two-dimensionally arranged (that is, a region indicated by a one-dot chain line in FIG. 4) is the detection unit P of the image sensor 1.

  In the present embodiment, a photodiode is used as the conversion unit 5. However, for example, a phototransistor or the like can be used.

  And as shown in FIG. 4, each resistance switch 6 from which resistance value changes with voltage application to the 1st electrode 5a of each conversion part 5 is electrically connected, respectively. A specific configuration of the conversion unit 5 including the resistance switch 6 according to this embodiment will be described later.

  In the present embodiment, a plurality of signal lines 7 are wired so as to be connected to the respective resistance switches 6 for each column of the respective conversion units 5 arranged in a two-dimensional manner. The resistance switch 6 accumulates electric charge in each conversion unit 5 when the resistance value is high resistance. When the resistance value is set to a low resistance state, the resistance switch 6 stores the electric charge accumulated in each conversion unit 5. The signal line 7 is emitted through the resistance switch 6.

  In addition, a bias line 8 is connected to each of the second electrodes 5 b of each converter 5. One bias line 8 is wired for each row of each conversion unit 5 arranged two-dimensionally, and each bias line 8 is connected to each terminal of the switching driver 10. .

  A bias power supply 11 is connected to the switching driver 10. The switching driver 10 is a voltage having a predetermined voltage value supplied from the bias power supply 11 in a normal case, that is, in a case other than the image data reading process described later. Vbias, that is, the above-described reverse bias voltage Vbias is applied to each bias line 8. Therefore, in a normal state, the reverse bias voltage Vbias is applied to the second electrode 5b of the conversion unit 5 via each bias line 8 and each connection line 8.

  In the present embodiment, the first power source that supplies the switching driver 10 with the voltage value of the voltage output from the bias power source 11 converted into a different voltage value between the switching driver 10 and the bias power source 11. The circuit 12a and the second power supply circuit 12b are connected to each other.

  As described above, the bias power supply 11 supplies the switching driver 10 with the reverse bias voltage Vbias having a predetermined voltage value. As described later, the first power supply circuit 12a has a voltage value lower than the reverse bias voltage Vbias. The second power supply circuit 12b supplies a voltage having a voltage value higher than the reverse bias voltage Vbias to the switching driver 10.

  The switching driver 10 is supplied with a voltage Vb to be applied to each bias line 8 from the bias power supply 11 and a reverse bias voltage Vbias supplied from the bias power supply 11 and the first power supply circuit 12a in a later-described image data read process. The resistance value of the resistance switch 6 is varied by switching between a voltage having a lower voltage value and a voltage having a voltage value higher than that supplied from the second power supply circuit 12b. This point will be described later.

  On the other hand, as shown in FIG. 4, each signal line 7 is connected to each readout circuit 14 built in the readout IC 13. In the present embodiment, the readout circuit 14 includes an amplifier circuit 15 and a correlated double sampling circuit 16. An analog multiplexer 17 and an A / D converter 18 are further provided in the reading IC 13.

In FIG. 4, the correlated double sampling circuit 16 is denoted as CDS. In the present embodiment, a reference potential V ₀ such as 0 [V] is applied to each signal line 7 from each readout circuit 13 side.

  In the present embodiment, when the image data is read from each conversion unit 5, the electric charge is transferred from each conversion unit 5 to the signal line 7 via a resistance switch 6 that is in a low resistance state as will be described later. When discharged, the amplifier circuit 15 outputs a voltage value corresponding to the amount of discharged charges.

  Then, the correlated double sampling circuit (CDS) 16 provided on the output side of the amplifier circuit 15 converts the voltage value Vin output from the amplifier circuit 15 before each charge is discharged from each converter 5 into each converter. After the charge is discharged from the unit 5, the voltage value Vfi output from the amplifier circuit 15 is subtracted, and the difference Vfi−Vin between these voltage values is output downstream as analog value image data. .

  The output analog value image data is sequentially transmitted to the A / D converter 18 via the analog multiplexer 17, and is sequentially converted into digital value image data by the A / D converter 18 to be stored in the storage means 21. Are output and stored sequentially.

  In the present embodiment, as described above, the image sensor 1 is used in the radiographic image capturing apparatus 100. In the radiographic image capturing apparatus 100, a voltage value (that is, a signal value) normally output from the amplifier circuit 15 is used. Is small, the correlated double sampling circuit 15 is used. However, when the image sensor 1 is used for another photographing apparatus, the signal value may be sufficiently larger than the noise signal. In such a case, it is not always necessary to use the correlated double sampling circuit 15 or the like.

  The control means 20 includes a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), an input / output interface, etc. (not shown) connected to the bus, an FPGA (Field Programmable Gate Array), or the like. It is configured. It may be configured by a dedicated control circuit.

  The control means 20 controls the operation of each member of the image sensor 1. For example, the switching driver 10, the bias power supply 11, the first power supply circuit 12 a, the second power supply circuit 12 b, the readout circuit 14, etc. As described above, control is performed such that image data is read out as image data by discharging electric charges from the respective converters 5 as described above. A specific control method in the image data reading process will be described later.

  As shown in FIG. 4, the control means 20 is connected with a storage means 21 composed of SRAM (Static RAM), SDRAM (Synchronous DRAM), etc., and a battery 22 for supplying power to each functional unit. Has been. In addition, a connection terminal 23 for charging the battery 22 by supplying power to the battery 22 from a charging device (not shown) is attached to the battery 22. In the present embodiment, the control unit 20 is connected to the antenna device 41 of the radiation image capturing apparatus 100 described above.

  Next, a specific configuration and the like of the conversion unit 5 including the resistance switch 6 in the image sensor 1 according to the present embodiment will be described. FIG. 5 is an enlarged plan view of a conversion unit including the resistance switch according to the present embodiment, and FIG. 6 is a cross-sectional view of one conversion unit along line YY in FIG.

  In the following description, the up and down direction is represented in accordance with the up and down direction in FIG. 6 representing each component of the conversion unit 5 (that is, the upper side in the figure is represented as “upper” or “upward”). The left-right direction is expressed in accordance with the left-right direction in FIGS.

  5 and 6 are described so that each component is easy to see, and the relative size, positional relationship, interval, thickness, and the like of each component do not necessarily reflect the actual configuration. In particular, in FIG. 5, it is described that the spaces between the respective conversion units 5 are widened, but actually, the interval between the respective conversion units 5 is made as narrow as possible to improve the aperture ratio of each conversion unit 5. Configured.

  As described above, in this embodiment, each conversion unit 5 includes the first electrode 5 a and the second electrode 5 b, and the second electrode 5 b of the conversion unit 5 is connected to the bias line 8. In addition, a resistance switch 6 is electrically connected to each first electrode 5a of the conversion unit 5, and each resistance switch 6 is connected to each signal line for each column of each conversion unit 5 arranged two-dimensionally. 7 is connected.

  And in the conversion part 5 of this embodiment, the 1st electrode 5a of the conversion part 5 and the one electrode 6c of the resistance switch 6 are made into the common electrode. That is, the first electrode 5 a functions as the first electrode 5 a of the conversion unit 5 and at the same time functions as one electrode 6 c of the resistance switch 6.

  And in the conversion part 5 of this embodiment, the resistance switch 6 is electrically connected with the 1st electrode 5a of the conversion part 5 by making the 1st electrode 5a into a common electrode with the resistance switch 6 in this way. It has come to be.

  In addition, although not shown, for example, one electrode 6c of the resistance switch 6 is separated from the first electrode 5 of the conversion unit 5 on a body portion 6b described later of the resistance switch 6, for example. The electrode of the resistance switch 6 and the first electrode 5a of the conversion unit 5 can be directly connected by, for example, stacking the first electrode 5a of the conversion unit 5 thereon. .

  Furthermore, for example, the resistance switch 6 is formed at an appropriate position on the substrate 4, and the conversion unit 5 is configured such that one electrode 6 c of the resistance switch 6 and the first electrode 5 a of the conversion unit 5 are connected by a conductive wire or the like. It is also possible to configure. Even with such a configuration, it is possible to electrically connect the resistance switch 6 and the first electrode 5a of the conversion unit 5.

  Hereinafter, in order to describe the specific configuration of the conversion unit 5 including the resistance switch 6 in the image sensor 1 according to the present embodiment more specifically, the manufacturing process will be described. FIG. 7 is a flowchart showing each step in the manufacturing process of the conversion unit including the resistance switch.

  First, as shown in FIG. 8A, a signal line 7 made of a metal wire such as aluminum is arranged in advance on the substrate 4, and a resistance switch is placed on the substrate 4 and the signal line 7 as shown in FIG. 8B. 6 electrodes 6a are stacked (step S1 in FIG. 6).

  In the present embodiment, the electrode 6a of the resistance switch 6 is made of TiN (titanium nitride). In the present embodiment, the electrode 6a is provided with a recess in the vicinity of the portion connected to the signal line 7, as shown in FIG.

  The resistance value of the resistance switch 6 to be described later is determined by various elements, and as one of the elements, as shown in FIG. 9A, the main body 6b of the resistance switch 6 (not shown in FIGS. 9A and 9B). 5 may be changed depending on the bonding area of the electrode 6a and the electrode 6c sandwiched from above and below (that is, the first electrode 5a in the present embodiment; the same shall apply hereinafter) through the main body 6b.

  In such a case, in the manufacturing process, it is necessary to accurately align the electrodes 6a and 6c of the resistance switch 6 and to accurately perform the relative arrangement of the electrodes 6a and 6c. In an actual manufacturing process such as a film forming process using a shadow mask, the accuracy of alignment or the like may not always be good. That is, in the actual process, the position of the electrode 6c may be shifted from the design position with respect to the electrode 6a.

  However, as in the present embodiment shown in FIG. 9A, the electrode 6a of the resistance switch 6 has a portion connected to the signal line 7 and a portion joined to the electrode 6c via the body portion 6b of the resistance switch 6. If a recess M is provided between them, even if the position of the electrode 6c stacked above is shifted in the left-right direction (see the arrow in the figure), one side of the joint portion between the electrode 6a and the electrode 6c of the resistance switch 6 is provided. The length a does not change, and the junction area is approximately a × b.

  In this case, if the position of the electrode 6c laminated on the upper side is shifted in the left-right direction, the area of the portion shown by hatching in FIG. 9A increases or decreases, so that the bonding area increases or decreases, but the increase or decrease is slight. Even if the position of the electrode 6c laminated on the right and left is shifted in the left-right direction, the joining area of the electrode 6a and the electrode 6c of the resistance switch 6 through the main body 6b is substantially a × b, and hardly changes. In practice, the junction area can be a × b.

  In the present embodiment, the electrode 6a of the resistance switch 6 is thus stacked with the recess M as shown in FIG. 9A, so that the electrode 6a and the body portion 6b of the resistance switch 6 are stacked. Even if the position of the electrode 6c is shifted, it is possible to keep the junction area between the electrode 6a and the electrode 6c through the main body 6b of the resistance switch 6 from approximately a × b.

  Therefore, when the resistance value of the resistance switch 6 changes depending on the junction area of the electrode 6a and the electrode 6c via the main body 6b, the alignment of the electrode 6a and the electrode 6c of the resistance switch 6 is performed precisely. Even if this is difficult, it is possible to minimize the influence of the change in the junction area and accurately prevent the resistance value of the resistance switch 6 from deviating from the designed resistance value.

  If the junction area between the electrode 6a and the electrode 6c of the resistance switch 6 is slightly deviated and the resistance value of the resistance switch 6 is slightly deviated from the set value, as shown in FIG. 9B, the resistance switch It is also possible to form the electrode 6a in a rectangular shape, for example, without providing a recess in the six electrodes 6a.

  On the other hand, as will be described later, the main body portion 6b of the resistance switch 6 is laminated above the electrode 6a of the resistance switch 6 (see FIG. 6). At this time, for example, as shown in FIG. Is in a state of being cut off from the substrate 4 and the signal line 7 (that is, a state in which no taper is provided), the main body portion 6b of the resistance switch 6 laminated thereon corresponds to the edge portion of the electrode 6a. There is a case where a break occurs at the portion (see the arrow in the figure).

  In particular, in the present embodiment, the main body portion 6b of the resistance switch 6 is formed in a thin film shape having a thickness of several nanometers to several tens of nanometers. When a break occurs in this way, it becomes difficult for current to flow at the break, and the resistance switch 6 may not perform a predetermined function.

  Therefore, in order to prevent such a situation from occurring, in the present embodiment, the edge portion of the electrode 6a is not separated from the substrate 4 or the signal line 7 as described above, and is shown in FIGS. 6 and 8B. As described above, the edge portion of the electrode 6a is formed to be tapered.

  As a method for forming the edge portion of the electrode 6a in a tapered manner in this way, for example, the following method can be employed.

  That is, for example, as shown in FIG. 11, the electrode 6a is laminated above the substrate 4 and the signal line 7 as shown in FIGS. 9A and 9B. Then, for example, the electrode 6a is laminated by using a shadow mask constituted by a base M1 having a shape so as to surround the electrode 6a and a mask material M2 having a planar opening of the electrode 6a to be formed.

  Then, in this way, alignment is performed so that the mask material M2 is not brought into close contact with the electrode 6a, and so, for example, sputtering film formation is performed in a state where the mask material M2 is lifted to some extent. When the treatment is performed in this manner, the sputtered molecules come into the gap between the electrode 6a and the mask material M2 (see the arrow in FIG. 11), and the edge portion of the electrode 6a can be accurately formed into a tapered shape. .

  In the manufacturing process, subsequently, as shown in FIGS. 5 and 6, the main body 6b of the resistance switch 6 is formed above the electrode 6a (step S2 in FIG. 7).

  In the present embodiment, the main body portion 6b of the resistance switch 6 is formed so as to cover the electrode 6a (that is, cover the electrode 6a). Similarly to the above, even if the relative position of the main body portion 6b of the resistance switch 6 with respect to the electrode 6a is slightly shifted with respect to the electrode 6a, the main body portion 6b of the resistance switch 6 is reliably connected between the electrode 6a and the electrode 6c. This is because the electrode 6a and the electrode 6c are not in direct contact (that is, are not electrically connected).

  However, if the electrode 6a and the electrode 6c can be configured not to be in direct contact with each other even if the resistor switch 6 is formed above the electrode 6a, the electrode 6a is not necessarily covered with the main body 6b of the resistor switch 6. do not have to.

  In the present embodiment, the resistance switch 6 includes a main body 6b made of titanium oxide (TiOx) whose resistance value is changed by an electric field formed in the resistance switch 6 when a voltage is applied. 6c (in the case of the present embodiment, the first electrode 5a) is sandwiched.

  The main body 6b of the resistance switch 6 can be a resistance switch using various known materials other than titanium oxide, and preferably, for example, Cu, Ni, Fe, Al, Hf, Zr, An oxide of a transition metal such as Ba, Sr, Ta, La, Si, or Y, or one having an oxygen defect is used. It is also possible to mix these metal oxides and metal oxides having different ratios such as oxygen (O) contained therein or to divide them into two layers.

  Subsequently, as shown in FIGS. 5 and 6, the first electrode 5 a of the conversion unit 5, which is a common electrode with the electrode 6 c in the present embodiment, is disposed at a predetermined position above the main body 6 b of the resistance switch 6. A layered structure is formed (step S3 in FIG. 7). In the present embodiment, as described above, the first electrode 5 a functions as the electrode 6 c on the opposite side of the electrode 6 a of the resistance switch 6 and also functions as one electrode of the conversion unit 5.

  Subsequently, as shown in FIGS. 5 and 6, the main body 5c of the conversion unit 5 is laminated and formed above the first electrode 5a (step S4 in FIG. 7).

  In the present embodiment, the main body 5c of the conversion unit 5 is formed in an n-type by doping a group VI element into hydrogenated amorphous silicon (a-Si) sequentially from the lower side (that is, the resistance switch 6 side). A layer 5d, an i layer 5e (so-called conversion layer) made of hydrogenated amorphous silicon, and a p layer 5f formed into a p-type by doping a hydrogenated amorphous silicon with a group III element are formed. .

  Then, when the light irradiated to the image sensor 1 (in this embodiment, the light irradiated to the radiation image capturing apparatus 1 is converted by the scintillator 3 (see FIG. 2)) enters the i layer 5e. Electron hole pairs are generated in the i layer 5e.

  As described above, when a reverse bias voltage is applied from the bias line 8 (see FIG. 4) to the second electrode 5b of the conversion unit 5, electrons generated in the i layer 5e are moved to the first electrode 5a side. The holes move to the second electrode b side. Therefore, electrons and holes generated in the converter 5c due to light irradiation move to the corresponding first electrode 5a and second electrode 5b side without recombination (that is, in FIG. 6, the i layer 5e). Within each other).

  And when the main-body part 5c of the conversion part 5 is formed, the 2nd electrode 5b formed as transparent electrodes, such as ITO (Indium Tin Oxide), will be further laminated | stacked further on it (step S5 of FIG. 7).

  In the present embodiment, as shown in FIG. 12, an insulating layer made of, for example, silicon nitride (SiN) or the like by sputtering or the like from above the main body 5c and the second electrode 5b of the converter 5 stacked in this way. 9 is formed to cover the resistance switch 6 and the main body 5c (step S6 in FIG. 7).

  In this state, a contact hole H as shown in FIG. 6 is formed in the insulating layer 9 above the second electrode 5b (step S7 in FIG. 7).

  At this time, if the contact hole H is formed in the insulating layer 9 by using, for example, an anisotropic plasma etching method, the edge portion of the contact hole H may be formed so as to stand up from the second electrode 5b. .

  However, when the edge portion of the contact hole H is formed so as to stand up like this, the bias line 8 formed so as to enter the contact hole H and be connected to the second electrode 5b as will be described later (FIG. 6). However, there is a possibility that the edge of the contact hole H will be cut off. When the step breaks, a necessary voltage cannot be applied from the bias line 8 to the second electrode 5b of the conversion unit 5.

  Therefore, in this embodiment, as a method for forming the contact hole H, a chemical dry etching method is adopted. In this method, the gas is decomposed in another reaction chamber, not directly above the portion of the insulating layer 9 where the contact hole H is to be formed, and the generated radicals are transported to the portion to perform the etching process.

  When such an etching process is performed, in addition to the feature that the insulating layer 9 and the like are not damaged, an etching process almost similar to an isotropic etching can be performed. Therefore, as shown in FIG. The edge portion of the contact hole H can be tapered. Since the edge portion of the contact hole H is tapered, it is possible to accurately prevent the bias line 8 from being cut at the edge portion of the contact hole H.

  Any technique other than chemical dry etching may be used as long as it can achieve the above-mentioned purpose. For example, if the cutting of the bias line 8 does not occur even if the plasma etching method is used, plasma is used. It is also possible to employ an etching method.

  When the tapered contact hole H is formed in the insulating layer 9 in this way, subsequently, the bias line 8 is wired on the insulating layer 9, and the bias line 8 is connected to the conversion unit 5 via the contact hole H. The second electrode 5b is connected (step S8 in FIG. 7). In the present embodiment, the bias line 8 is made of a metal wire such as aluminum.

  In FIG. 6 and the like, the case where the bias line 8 is directly wired on the insulating layer 9 having projections and depressions is shown, but in order to prevent the bias line 8 from being unnecessarily cut, for example, the insulating layer 9 In order to eliminate the unevenness, the bias line 8 may be wired after the surface of the insulating layer 9 is flattened by filling the concave portion of the insulating layer 9 with a resin or the like.

  5 and 6 show the case where the contact hole H is formed immediately above the electrode 6a of the resistance switch 6 and the main body 6b. However, the formation position of the contact hole H and the wiring of the bias line 8 are shown. The position is not limited to this. The contact hole H and the bias line 8 may be formed and wired at positions other than the above. For example, the contact hole H may be provided at the end of the second electrode 5b of the conversion unit 5 or the like. It is also possible to do. It is also possible to configure the bias line 8 to be wired in a portion between the conversion units 5.

  Next, a description will be given of a specific control method and the like in the image data reading process when shooting is performed using the image sensor 1 according to the present embodiment having the above-described configuration. In addition, the operation of the image sensor 1 and the radiographic image capturing apparatus 100 according to the present embodiment will also be described.

  In the following, a case where radiographic imaging is performed using the radiographic imaging apparatus 100 using the image sensor 1 according to the present embodiment will be described. For example, the imaging sensor 1 is another imaging device such as a digital camera. Needless to say, the image sensor is used in a control method suitable for it.

  In the present embodiment, the control means 20 (see FIG. 4) of the image sensor 1 in the radiographic image capturing apparatus 100 receives the radiation from the switching driver 10 before the radiation image capturing apparatus 100 is irradiated with radiation. Each resistance switch 6 is switched to a high resistance state by controlling the voltage value of the voltage applied to each second electrode 5b of each converter 5 via each bias line 8.

  By switching the resistance switch 6 of each conversion unit 5 to a high resistance state, the irradiated radiation is converted into light by the scintillator 3, and the converted light is irradiated, whereby the i layer 5e of each conversion unit 5 is irradiated. When charge is generated in the converter, the charge is appropriately accumulated in each conversion unit 5. In this way, the control unit 20 causes each conversion unit 5 to shift to a charge accumulation state in which charges generated in the i layer 5e of each conversion unit 5 due to radiation irradiation are accumulated in each i layer 5e. It has become.

  When the irradiation of the radiation is completed after the conversion units 5 are shifted to the charge accumulation state as described above, the control unit 20 controls the operation of the switching driver 10, the readout circuit 14, and the like (see FIG. 4). Thus, each conversion unit 5 performs image data read processing for reading out the charges generated in each i-layer 5e as a result of radiation irradiation as image data.

  In this image data reading process, in the present embodiment, the control unit 20 controls the voltage value of the voltage applied from the switching driver 10 to each conversion unit 5 via each bias line 8 to control each resistance switch 6. Switching to the low resistance state allows each readout circuit 14 to read out image data.

  Then, the control means 20 sequentially performs this process while shifting the bias line 8 that switches the voltage value of the voltage applied from the switching driver 10, and charges are transferred from the conversion units 5 connected to the bias lines 8. By sequentially discharging the signal lines 7 and sequentially reading them as image data by the respective readout circuits 14, the image data is read out from the respective converters 5.

  Hereinafter, a specific control method of the above processing by the control means 20 will be described.

  As will be described later, the resistance switch 6 mainly includes a unipolar (also referred to as non-polar) resistance switch and a bipolar resistance switch. First, a bipolar resistance switch is used as the resistance switch 6. A description will be given of the image data read processing by the control means 20 in the case of such a case.

  FIG. 13 shows that when the applied voltage V exceeds a certain threshold value of the positive voltage, the low resistance state is switched to the high resistance state, and when the applied voltage V exceeds a certain threshold value of the negative voltage, the high resistance state is changed to the low resistance state. It is a graph explaining an example of the bipolar resistance switch of the type switched to.

  In this type of bipolar resistance switch 6, as shown in FIG. 13, the resistance value of the resistance switch 6 is not changed until the direction of the voltage V (also referred to as polarity) applied to the resistance switch 6 is reversed between positive and negative. A transition can be made between a high resistance state and a low resistance state.

  That is, for example, when the resistance switch 6 in a high resistance state has a voltage V applied to the resistance switch 6, that is, the absolute value of the potential V between the electrode 6a and the first electrode 5a in the resistance switch 6 exceeds a predetermined voltage value Vrs. The resistance value of the resistance switch 6 transitions to a low resistance state. Further, when the resistance value of the resistance switch 6 is in a low resistance state, if the polarity of the voltage V applied to the resistance switch 6 is changed and its absolute value exceeds a predetermined voltage value Vst, the resistance of the resistance switch 6 The value transitions to a high resistance state.

  In the bipolar resistance switch 6 of which the resistance value changes according to the voltage V to be applied, the resistance value is changed by changing the voltage value of the voltage V to be applied while changing the direction of the voltage V to be applied. The resistance value of the switch 6 can be varied.

  In the case where the above-described bipolar resistance switch is used as the resistance switch 6, the control means 20 is configured to perform image data read processing and the like by controlling as follows. In this case, in the charge accumulation state, the resistance value of the resistance switch 6 is set to a high resistance state, and in the image data reading process, the resistance value of the resistance switch 6 is switched to a low resistance state. Hereinafter, this will be specifically described with reference to FIG.

  FIG. 14 shows a time such as the voltage Vb applied to the second electrode 5b of the conversion unit 5 and the voltage V applied between the electrode 6a of the resistance switch 6 and the first electrode 5a when the bipolar resistance switch 6 is used. It is a graph showing general transition.

  At the time of the left end of FIG. 14, it is assumed that each conversion unit 5 has already been in a high resistance state of the resistance value of the resistance switch 6. In this state, the control means 20 uses the voltage applied to the second electrode 5b of each converter 5 as Vb, and the reverse bias voltage of the predetermined voltage value Vbias supplied from the bias power supply 11 (see FIG. 4) is It is assumed that each conversion unit 5 is in a charge accumulation state by being applied from the switching driver 10 to the second electrode 5b of each conversion unit 5 via each bias line 8.

  In this state, since the resistance value of the resistance switch 6 is in a high resistance state, the charge generated in the i layer 5e (see FIG. 6 and the like) of each converter 5 hardly flows out to the signal line 7. Yes. Hereinafter, the description starts from this state.

  On the other hand, in each conversion unit 5, a so-called dark current (also referred to as dark charge) is normally generated due to thermal excitation by heat (temperature) of each conversion unit 5 itself, and this dark current is a high resistance. Instead of being blocked by the resistance switch 6 and flowing out to the signal line 7, it is accumulated in the main body 5 c of each converter 5. Therefore, as shown in the left end portion of FIG. 14, the voltage V of the first electrode 5a is in a state of gradually decreasing according to the amount of dark current generated.

  As shown in FIG. 14, when radiation is subsequently applied to the radiation image capturing apparatus 100 (that is, when light is applied to the image sensor 1), the above-mentioned is performed in the i layer 5 e of the conversion unit 5. An electron-hole pair is generated in the first electrode, and the generated electrons and holes move to the first electrode 5a and the second electrode 5b, respectively, and are separated. Therefore, at this time, the potential difference V between the electrode 6a of the resistance switch 6 and the first electrode 5a greatly increases according to the amount of charge generated, and the voltage V of the first electrode 5a greatly decreases.

  Then, when the irradiation of radiation to the radiographic image capturing apparatus 100 is completed (that is, when the irradiation of light to the image sensor 1 is completed), the control unit 20 starts reading processing of image data from each conversion unit 5. ing.

  In the image data reading process, as shown in FIG. 14, the control means 20 reduces the voltage Vb applied from the switching driver 10 to the first bias line 8a at once from the reverse bias voltage Vbias. That is, the voltage Vb applied from the switching driver 10 to the bias line 8a is supplied from the first power supply circuit 12a from the reverse bias voltage Vbias having a predetermined voltage value supplied from the bias power supply 11 (see FIG. 4). The voltage Vb is lower than the reverse bias voltage Vbias. At this time, the voltage Vb applied to the other bias lines 8b, 8c,... Remains the reverse bias voltage Vbias.

  Then, since the absolute value of the potential difference V between the electrode 6a of the resistance switch 6 and the first electrode 5a exceeds a predetermined voltage value Vst, the resistance value of the bipolar resistance switch 6 transitions from a high resistance state to a low resistance state. To do. Therefore, the charge generated in the i layer 5e of the conversion unit 5 is released to the signal line 7 through the resistance switch 6 in a low resistance state.

  And since the quantity of the electron and the hole which were accumulate | stored in the main-body part 5c of the conversion part 5, and were isolate | separated into the 1st electrode 5a and the 2nd electrode 5b reduces, the electric potential difference between the 1st electrode 5a and the 2nd electrode 5b That is, the difference V−Vb between the voltage V and the voltage Vb increases so as to return to the original potential difference before irradiation with radiation. Accordingly, the potential difference V between the electrode 6a of the resistance switch 6 and the first electrode 5a is reduced, and the voltage V of the first electrode 5a is increased.

  Further, when the charge generated in the i layer 5e of the conversion unit 5 is released to the signal line 7 through the resistance switch 6 in a low resistance state, each charge flows into the corresponding readout circuit 14, As described above, the data is read out as image data by the readout circuit 14 and the like, respectively output to the storage means 21 and sequentially stored.

  As shown in FIG. 14, the control means 20 starts the first switching driver 10 from the switching driver 10 in order to shift the resistance value of the resistance switch 6 to the high resistance state at the stage where the discharge of the electric charges from each conversion unit 5 is finished. The voltage Vb applied to the bias line 8a is increased at a stroke so that the voltage Vb becomes a predetermined positive voltage value.

  That is, the control means 20 has a voltage value lower than the reverse bias voltage Vbias supplied from the first power supply circuit 12a (see FIG. 4) by applying the voltage Vb applied from the switching driver 10 to the bias line 8a. The voltage Vb is switched to the voltage Vb having a predetermined positive voltage value supplied from the second power supply circuit 12b.

  Then, the potential difference V between the electrode 6a of the resistance switch 6 and the first electrode 5a, that is, the voltage V of the first electrode 5a is pushed up at a stretch to change to a positive voltage value and exceed a predetermined voltage value Vrs. For this reason, the resistance value of the bipolar resistance switch 6 transitions from a low resistance state to a high resistance state this time.

  However, in this state, a so-called forward bias is applied to the main body 5c of the converter 5, and thus a large current flows through the converter 5 including the resistance switch 6.

  For this reason, as shown in FIG. 14, when the resistance switch 6 of each converter 5 connected to the bias line 8a is in a high resistance state, the control means 20 immediately applies the switching driver 10 to the bias line 8a. The voltage Vb to be returned is returned to the original reverse bias voltage Vbias. That is, the control unit 20 supplies the voltage Vb applied to the bias line 8a from the switching driver 10 from the bias power supply 11 from the voltage Vb having a predetermined positive voltage value supplied from the second power supply circuit 12b. The reverse bias voltage Vbias having a predetermined voltage value is switched.

  In the present embodiment, the conversion units 5 connected to the bias line 8a are thus returned to the original charge accumulation state.

  In this way, if the resistance switch 6 is switched back to the high resistance state and immediately returned to the state in which the reverse bias voltage Vbias is applied to the conversion unit 5, the period during which each conversion unit 5 is forward-biased can be obtained. Very shortened.

  Even if a forward bias is applied to each converter 5, there is a time constant delay until a large current actually flows through each converter 5, so that the voltage Vb applied to each converter 5 as described above. Is immediately switched to the reverse bias voltage Vbias, even if the voltage Vb is varied as described above, it is practically possible to prevent a large current from flowing in each converter 5.

  When the above processing for the bias line 8a is completed, the control means 20 performs reading processing on the bias line 8b in the same manner, and reads image data from each converter 5 connected to the bias line 8b. In this manner, the control unit 20 sequentially performs the image data read processing while shifting the bias line 8 for switching the voltage Vb to be applied, so that each conversion unit 5 connected to each bias line 8 ( That is, the image data is read out from all the conversion units 5).

  On the other hand, when a unipolar resistance switch is used as the resistance switch 6, image data read processing or the like can be performed in the same manner. FIG. 15 shows an electrode 6a-first electrode 5a (that is, electrode 6c) in a unipolar resistance switch 6 of a type in which a high resistance state and a low resistance state are switched when the absolute value of the applied voltage V exceeds a threshold value. It is a graph explaining the relationship between the electric potential V between and the electric current I which flows.

  In this type of unipolar resistance switch 6, as shown in FIG. 15, the direction (also referred to as polarity) of the voltage V applied to the resistance switch 6 is the same (ie, the applied voltage V is, for example, In a state where the voltage is a negative value), the resistance value transitions between a high resistance state and a low resistance state according to the applied voltage V.

  That is, for example, when a negative voltage V is applied to this type of unipolar resistance switch 6 to switch the resistance state, for example, when the resistance value of the resistance switch 6 is in a low resistance state, When the applied voltage V is decreased and the voltage V falls below the threshold value Vrs, the resistance value of the resistance switch 6 transitions from a low resistance state to a high resistance state as shown in FIG. Then, when the voltage is further lowered and the voltage V becomes lower than the threshold value Vst, the resistance value of the resistance switch 6 is changed from the high resistance state to the low resistance state.

  Further, the voltage V to be applied is increased, and when the voltage V further increases and exceeds the threshold value Vrs on the positive voltage side, the resistance value of the resistance switch 6 transitions from the low resistance state to the high resistance state. .

  Even when the unipolar resistance switch 6 whose resistance value changes in accordance with the voltage V applied in this way is used, as shown in FIG. 16, for example, the voltage Vb applied to the second electrode 5b of the conversion unit 5 , And the voltage V between the electrode 6a of the resistance switch 6 and the first electrode 5a is varied, whereby the resistance value of the resistance switch 6 can be varied.

  Therefore, even when a unipolar resistance switch is used as the resistance switch 6, image data can be accurately read out from each conversion unit 5 as in the case of using the bipolar resistance switch 6 shown in FIG. It becomes. As shown in FIG. 16, in the case of the unipolar type, unlike the case of the bipolar type shown in FIG. 14, no forward bias is applied to the conversion unit 5 (that is, it is necessary to apply a positive voltage as the voltage Vb). There is a merit that

The same applies to the bipolar resistance switch 6 described above, but the resistance switch 6 has a resistance value in a high resistance state and a resistance value in a low resistance state from the viewpoint of the S / N ratio in the read image data. It is desirable to use one having a ratio to the value of 10 ⁵ or more.

  Further, as described above, when the resistance switch 6 is in a high resistance state, dark current continues to be accumulated in each conversion unit 5, so that the accumulated dark current or the like is discharged from each conversion unit 5 to each signal line 7. In some cases, the reset process of each conversion unit 5 to be removed is performed.

  Also in the reset process of each conversion unit 5, the voltage Vb applied to the second electrode 5 b of each conversion unit 5 from the switching driver 10 via each bias line 8 is read out in the same manner as described above. The resistance value of each resistance switch 6 is switched between a high resistance state and a low resistance state by lowering or raising in the same manner as in the above, and charges remaining in each conversion unit 5 are accurately removed. can do.

  As described above, according to the image sensor 1 and the radiographic image capturing apparatus 100 according to the present embodiment, since the resistance switch 6 is used as the switch element of each conversion unit 5, for example, as illustrated in FIG. The structure of the conversion unit 5 can be further simplified.

  Further, when the resistor switch 6 is used as the switch element of each conversion unit 5 as in the image sensor 1 and the radiographic imaging apparatus 100 according to the present embodiment, the on / off operation of the resistor switch 6, that is, a high resistance operation. The transition between the state and the low resistance state can be performed by varying the voltage Vb applied to the second electrode 5b of each converter 5 via the bias line 8. Then, for example, since a TFT is not used as a switching element as in the conventional conversion unit A shown in FIG. 17, a voltage for turning on / off the TFT is applied to the image sensor 1 and the radiation image capturing apparatus 100. There is no need to provide the scanning line Ga.

  As described above, in the conventional image sensor and radiographic apparatus, the scanning line Ga is provided in order to secure a space for providing the scanning line Ga on the substrate and to prevent a short circuit from occurring with other wirings. However, in the image sensor 1 and the radiographic imaging apparatus 100 according to the present embodiment, the scanning line Ga is not necessary, and it is not necessary to take the above-described measures. .

  Therefore, beneficial effects such as an increase in the degree of freedom of layout of the conversion unit 5, the resistance switch 6, the signal line 7, the bias line 8, and the like on the substrate 4 of the image sensor 1 and the radiation image capturing apparatus 100 can be obtained.

  In addition, in the conventional conversion part manufacturing process, in order to form TFTs, PEP (Photo Etching Process) consisting of various processes such as film formation, resist coating, exposure, development, post-baking, etching, and resist stripping is repeated. There was a need to do. However, in the manufacturing process of the conversion unit 5 according to the present embodiment, the resistive switches 6 and the like can be stacked by a simpler method using, for example, a shadow mask.

  Therefore, the conversion unit 5 according to the present embodiment can be manufactured by a simple manufacturing process, and the conversion unit 5, the image sensor 1, and the radiation image capturing apparatus 100 according to the present embodiment are manufactured by a simpler production process. It becomes possible. For this reason, it is possible to improve the productivity of the conversion unit 5, the image sensor 1, and the radiation image capturing apparatus 100, and to obtain a beneficial effect that it is possible to improve the production yield. It becomes possible.

  Needless to say, the present invention is not limited to the above-described embodiment, and can be appropriately changed without departing from the gist of the present invention.

  There is a possibility of use in the field of image sensors and radiographic imaging apparatuses using the same.

DESCRIPTION OF SYMBOLS 1 Image sensor 4 Board | substrate 5 Conversion part 5a 1st electrode, electrode 5b of resistance switch 2nd electrode 6 Resistance switch 7 Signal line 8 Bias line 10 Switching driver 14 Reading circuit 20 Control means 100 Radiation imaging device V Applied to resistance switch Voltage Vb Voltage applied to the converter

Claims (9)

A plurality of converters including a first electrode and a second electrode, two-dimensionally arranged on the substrate;
Each resistance switch that is provided so as to be electrically connected to the first electrode of each of the conversion units, and whose resistance value changes by voltage application;
Each signal line wired so as to be connected to each of the resistance switches for each column of the conversion units arranged two-dimensionally,
For each row of each of the converters arranged in a two-dimensional manner, each bias line wired to be connected to the second electrode of each converter, and applying a voltage to each converter,
A switching driver for switching the voltage value of the voltage applied to each bias line;
Each readout circuit provided for each of the signal lines, which converts the charges discharged from the conversion unit to the corresponding signal lines into image data and reads out the image data;
Control means for controlling the operation of at least the switching driver and each readout circuit to read out the image data from the respective conversion units to read out the electric charges generated in the respective conversion units by the light irradiation as the image data. When,
An image sensor comprising: The control means includes
A voltage value of a voltage applied to each conversion unit from each switching driver via each bias line is controlled to switch each resistance switch to a high resistance state, and generated in each conversion unit by light irradiation. Transition to a charge accumulation state in which charges are accumulated in each of the conversion units,
After the charge accumulation state, when the image data is read out, the voltage value of the voltage applied from the switching driver to the converters via the bias lines is controlled to reduce the resistance switches. 2. The process of switching to a resistance state and causing each of the readout circuits to read out the image data is performed while shifting the bias line for switching the voltage value of the applied voltage. The image sensor described in 1.   In each of the conversion units, the first electrode and one of the two electrodes of the resistance switch are a common electrode, whereby the first electrode of the conversion unit and the resistance switch are electrically connected. The image sensor according to claim 1, wherein the image sensor is provided so as to be connected to each other.   In each of the conversion units, the first electrode and one of the two electrodes of the resistance switch are directly connected to electrically connect the first electrode of the conversion unit and the resistance switch. The image sensor according to claim 1, wherein the image sensor is provided so as to be connected.   The image sensor according to claim 3, wherein the conversion unit and the resistance switch are stacked. The resistive switch is any one of claim 2 of the fifth term of the ratio of the resistance value in the state of the resistance value and a low resistance in a state of high resistance, characterized in that there is a 10 ⁵ or more The image sensor according to item. As the resistance switch, a unipolar resistance switch or a bipolar resistance switch is used,
In the reading process of the image data, the control means reduces the voltage value of the voltage applied to each conversion unit from the switching driver via the bias line for each bias line. The voltage value of the voltage applied to the switch is lowered to switch the resistance switch from a high resistance state to a low resistance state, according to any one of claims 2 to 6. The image sensor described.   When the reading process of the image data for each of the bias lines is completed, the control unit increases the voltage value of the voltage applied from the switching driver to the conversion units via the bias lines. The image sensor according to claim 7, wherein the resistance switch is switched from a low resistance state to a high resistance state by increasing a voltage value of an applied voltage. The image sensor according to any one of claims 1 to 8,
When irradiated with radiation, a scintillator that converts the radiation into light and outputs the light to each conversion unit;
A radiographic imaging apparatus comprising:

Images