JP5337281B2 - X-ray inspection system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an X-ray inspection system that has a solid state image pickup device capable of high speed operation. <P>SOLUTION: The X-ray inspection system images X-rays output from an X-ray generation device and transmitted through an object of inspection by means of a solid state image pickup device 1A to inspect the object of inspection. The solid state image pickup device 1A includes a light reception section 10A and a signal readout section 20. The light reception section has M&times;N pixel sections arrayed in M rows and N columns. In a first imaging mode, voltage values depending on amounts of charges generated in photodiodes of the M&times;N pixel sections of the light reception section are output from the signal readout section. In a second imaging mode, voltage values depending on amounts of charges generated in the photodiodes of pixel sections included in a specific region of consecutive M<SB POS="POST">1</SB>rows in the light reception section are output from the signal readout section. The direction of length of the specific region in the light reception section in the second imaging mode is perpendicular to the direction of movement of the solid state image pickup device. <P>COPYRIGHT: (C)2012,JPO&amp;INPIT

Description

  The present invention relates to an X-ray inspection system including a solid-state imaging device.

  As a solid-state imaging device, a device using CMOS technology is known, and among them, a passive pixel sensor (PPS) type is known. A PPS type solid-state imaging device includes a light receiving unit in which PPS type pixel units including photodiodes that generate an amount of electric charge according to incident light intensity are two-dimensionally arranged in M rows and N columns. The charge generated in the photodiode in response to the incident is accumulated in the capacitive element in the integrating circuit, and a voltage value corresponding to the amount of accumulated charge is output.

  In general, the output ends of each of the M pixel units in each column are connected to the input ends of the integration circuits provided corresponding to the columns via readout wirings provided corresponding to the columns. Has been. Then, for each row from the first row to the Mth row, the charge generated in the photodiode of the pixel portion is input to the corresponding integration circuit through the corresponding readout wiring, and the charge is supplied from the integration circuit. A voltage value corresponding to the amount is output.

  PPS solid-state imaging devices are used in various applications, for example, combined with a scintillator unit and used as an X-ray flat panel in medical and industrial applications. More specifically, X-ray CT devices and microfocus X It is also used in line inspection equipment. An X-ray inspection system disclosed in Patent Document 1 is a system that inspects an inspection object by imaging X-rays output from an X-ray generator and transmitted through the inspection object with a solid-state imaging device. It is said that X-rays transmitted through an object can be imaged in a plurality of types of imaging modes by a solid-state imaging device. Among these plural types of imaging modes, the imaging regions in the light receiving unit are different from each other.

International Publication No. 2006/109808 Pamphlet

  Japanese Patent Application Laid-Open No. 2004-228561 has a description that the imaging region in the light receiving unit of the solid-state imaging device is different depending on the imaging mode, but does not disclose any configuration or operation of the solid-state imaging device. However, the present inventor has found that there is a problem that the solid-state imaging device cannot operate at high speed depending on the configuration of the solid-state imaging device.

  The present invention has been made to solve the above problems, and an object of the present invention is to provide an X-ray inspection system including a solid-state imaging device capable of high-speed operation.

An X-ray inspection system according to the present invention includes a solid-state imaging device and an X-ray generation device, images the X-rays output from the X-ray generation device and transmitted through the inspection target, and images the inspection target. X-ray inspection system for inspecting The solid-state imaging device includes (1) M × N pixel units P _1,1 each including a photodiode that generates an amount of charge corresponding to incident light intensity, and a readout switch connected to the photodiode. To P _{M, N} are two-dimensionally arranged in M rows and N columns, and (2) a readout switch for each of the _M pixel units P _{1, n to} P _{M, n} in the n-th column in the light receiving unit, A readout wiring L _O that is connected and reads out the charge generated in the photodiode of any one of the _M pixel portions P _{1, n to} P _{M, n} through the readout switch of the pixel portion. _{, n} and (3) is connected to each of the read wirings L _{O, 1 to} L _{O, N} and holds a voltage value corresponding to the amount of charge input via the read wirings L _{O, n} and holds the voltage value A signal readout unit that sequentially outputs the voltage values obtained, and (4) each of the M × N pixel units P _{1,1 to} P _{M, N} in the light receiving unit. Controls the open / close operation of the readout switch, and also controls the output operation of the voltage value in the signal readout unit, and is generated in each photodiode of M × N pixel units P _{1,1 to} P _{M, N} in the light receiving unit And a control unit that outputs a voltage value corresponding to the amount of electric charge from the signal reading unit. Further, the control unit (a) in the first imaging mode, a voltage corresponding to the amount of charge generated in each of the M × N pixel units P _{1,1 to} P _{M, N} in the light receiving unit. (B) the amount of charge generated in the photodiodes of the pixel portions P _{m, n} included in the specific range of the continuous M ₁ row in the light receiving portion in the second imaging mode. A voltage value corresponding to the signal is output from the signal reading unit. Furthermore, the solid-state imaging device and the X-ray generator can be turned around the inspection target, or the solid-state imaging device can be linearly displaced with respect to the inspection target. It is characterized in that the longitudinal direction of a specific range in the light receiving unit in the second imaging mode is perpendicular to the moving direction of the solid-state imaging device at the time of displacement. Further, readout wiring line on one side of the specified range L _{O, 1} ~L _O, the signal readout section connected to each _N, the readout wiring on the other side of the specific range L _{O, 1} ~L _{O, N} respectively Further, a discharge switch for discharging the junction capacitance portion of the photodiode of each pixel portion is provided. However, M and N are integers of 2 or more, M ₁ is an integer of less than M, m is an integer of 1 to M, and n is an integer of 1 to N.

In the solid-state imaging device of the X-ray inspection system according to the present invention, the charge generated in response to light incident on the photodiode in each pixel unit P _{m, n} is controlled by the control unit. Is closed, the signal is input to the signal readout section through the readout switch and readout wiring L _{O, n} . The signal reading unit outputs a voltage value corresponding to the input charge amount. This solid-state imaging device has a first imaging mode and a second imaging mode. Under the control of the control unit, in the first imaging mode, a voltage value corresponding to the amount of charge generated in each photodiode of the M × N pixel units P _{1,1 to} P _{M, N} in the light receiving unit is a signal. Output from the reading unit. On the other hand, in the second imaging mode, a voltage value corresponding to the amount of charge generated in the photodiode of each pixel unit P _{m, n} included in a specific range of continuous M ₁ rows in the light receiving unit is output from the signal reading unit. Is done.

In the solid-state imaging device of the X-ray inspection system according to the present invention, in the second imaging mode, the control unit counts the range of M ₁ rows counting from the row closest to the signal readout unit among the M rows in the light receiving unit. As the specific range, it is preferable that a voltage value corresponding to the amount of charge generated in the photodiode of each pixel unit P _{m, n in} the specific range is output from the signal reading unit.

The solid-state imaging device of the X-ray inspection system according to the present invention includes a separation provided on each readout wiring L _{O, n} between the specific range in the light receiving unit and another range excluding the specific range. Preferably, the controller further includes a switch for closing, and the controller closes the switch for separation in the first imaging mode, and opens the switch for separation in the second imaging mode.

  In the solid-state imaging device of the X-ray inspection system according to the present invention, the control unit varies the gain, which is the ratio of the output voltage value to the input charge amount in the signal readout unit, between the first imaging mode and the second imaging mode. Is preferred.

The solid-state imaging device of the X-ray inspection system according to the present invention preferably further includes a scintillator unit provided so as to cover the M × N pixel units P _{1,1 to} P _{M, N} in the light receiving unit.

  In the X-ray inspection system according to the present invention, the X-ray generator outputs X-rays at a predetermined divergence angle in the first output mode, and from the predetermined divergence angle in the second output mode. When the X-ray is output at a narrow divergence angle and the X-ray generator outputs X-rays in the first output mode, the solid-state imaging device operates in the first imaging mode, and the X-ray generator is X in the second output mode. It is preferable that the solid-state imaging device operates in the second imaging mode when outputting a line.

  The X-ray inspection system according to the present invention can operate at high speed.

It is a figure showing composition of solid imaging device 1A concerning a 1st embodiment. It is a figure which shows the cross section of 1 A of solid-state imaging devices which concern on 1st Embodiment. 3 is a circuit diagram of each of a pixel unit P _{m, n} , an integration circuit _Sn, and a holding circuit H _{n of the} solid-state imaging device 1A according to the first embodiment. FIG. It is a timing chart explaining operation | movement of 1 A of solid-state imaging devices which concern on 1st Embodiment. It is a timing chart explaining operation | movement of 1 A of solid-state imaging devices which concern on 1st Embodiment. It is a timing chart explaining operation | movement of 1 A of solid-state imaging devices which concern on 1st Embodiment. It is a figure which shows the structure of the solid-state imaging device 1B which concerns on 2nd Embodiment. 1 is a configuration diagram of an X-ray inspection system 100 according to the present embodiment. It is a figure which shows the modification of the structure of solid-state imaging device 1A, 1B which concerns on this embodiment.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the accompanying drawings. In the description of the drawings, the same elements are denoted by the same reference numerals, and redundant description is omitted.

  First, the solid-state imaging device 1A according to the first embodiment will be described. FIG. 1 is a diagram illustrating a configuration of a solid-state imaging device 1A according to the first embodiment. A solid-state imaging device 1A shown in this figure includes a light receiving unit 10A, a signal reading unit 20, an AD conversion unit 30, and a control unit 40A. In addition, when used for X-ray detection, a scintillator unit is provided so as to cover the light receiving unit 10A of the solid-state imaging device 1A.

The light receiving unit 10A is configured such that M × N pixel units P _{1,1 to} P _{M, N} are two-dimensionally arranged in M rows and N columns. The pixel part P _{m, n} is located in the m-th row and the n-th column. Each pixel portion P _{m, n} is arranged at a pitch of 100 μm, for example. Here, M and N are each an integer of 2 or more, m is an integer of 1 to M, and n is an integer of 1 to N. Each pixel unit P _{m, n} is of the PPS system and has a common configuration.

Note that the light receiving unit 10A may have a pixel unit including a photodiode around the M × N pixel units P _{1,1 to} P _{M, N} two-dimensionally arranged in M rows and N columns. However, these surrounding pixel portions are covered with a shielding portion that prevents X-rays from entering the signal readout portion 20 and the like, and light does not enter and no charge is generated. The light receiving unit 10A includes at least M × N pixel units P _{1,1 to} P _{M, N} two-dimensionally arranged in M rows and N columns as effective pixel units for imaging.

Each of the N pixel units P _{m, 1 to} P _{m, N} in the m-th row is connected to the control unit 40A by the m-th row selection wiring LV _{, m} . M pixel portions P _{1, n} to P _{M, n} respective output terminals of the n-th column is for the n-th column readout wiring L _O, by _n, and is connected to the integrating circuit S _n of the signal readout section 20 .

The signal reading unit 20 includes N integration circuits S _{1 to} S _N and N holding circuits H _{1 to} H _N. Each integrating circuit _Sn has a common configuration. Moreover, the holding circuits H _n have a common configuration.

Each integrating circuit S _n readout wiring L _{O, n} and has an input terminal connected to, and accumulates charges input to this input terminal, the output terminal a voltage value corresponding to the accumulated charge amount output to the holding circuit _{H n.} The N integrating circuits _S 1 to S _N, respectively, connected to the control unit 40A by a reset wiring _{L R,} and also connected to the control unit 40A by a gain setting wiring _{L G.}

Each holding circuit H _n has an input terminal connected to the output terminal of the integrating circuit S _n , holds a voltage value input to the input terminal, and the held voltage value is connected to the voltage output wiring from the output terminal Output to L _out . The N holding circuits _H 1 to H _N, respectively, are connected to the controlling section 40A by a holding wiring _{L H.} Moreover, each holding circuit H _n is connected the n column selecting wiring L _H, and a control unit 40A by _n.

The AD conversion unit 30 inputs a voltage value output from each of the _N holding circuits H _{1 to} H _N to the voltage output wiring L _out and performs AD conversion processing on the input voltage value (analog value). And outputs a digital value corresponding to the input voltage value.

The control unit 40A outputs the m-th row selection control signal Vsel (m) to the m-th row selection wiring LV _{, m,} and outputs the m-th row selection control signal Vsel (m) to the Nth row selection control signal Vsel (m). Each pixel portion P _{m, 1 to} P _{m, N} is given. The M row selection control signals Vsel (1) to Vsel (M) are sequentially set to significant values. The control unit 40A includes a shift register to sequentially output M row selection control signals Vsel (1) to Vsel (M) as significant values.

Control section 40A, the n-th column selection control signal Hsel (n) to the n-th column selecting wiring L _H, and outputs to _n, gives the n-th column selecting control signal Hsel (n) to the holding circuit H _n. N column selection control signals Hsel (1) to Hsel (N) are also successively set to significant values. The control unit 40A includes a shift register in order to sequentially output N column selection control signals Hsel (1) to Hsel (N) as significant values.

The control unit 40A outputs a reset control signal Reset to the reset wiring L _R, giving the reset control signal Reset to each of the N integrating circuits S ₁ to S _N. Control unit 40A outputs a gain setting signal Gain to the gain setting wiring L _G, giving the gain setting signal Gain to each of the N integrating circuits S ₁ to S _N. Control unit 40A outputs a hold control signal Hold to the holding wiring L _H, gives the holding control signal Hold to the N holding circuits H ₁ to H _N, respectively. Further, although not shown, the control unit 40A also controls the AD conversion processing in the AD conversion unit 30.

Control unit 40A, as described above, M × N pixel units _{P 1, 1} to P _M in the photodetecting section _10A, and controls the _N respective opening and closing operation of the readout switch SW _1, the signal readout section 20 Controls voltage value holding and output operations. As a result, the control unit 40A uses the voltage value corresponding to the amount of charge generated in each photodiode of the M × N pixel units P _{1,1 to} P _{M, N} in the light receiving unit 10A as frame data as a signal readout unit. 20 to repeatedly output.

FIG. 2 is a diagram illustrating a cross-section of the solid-state imaging device 1A according to the first embodiment. In the solid-state imaging device 1 </ b> A, a semiconductor substrate 3 is attached to a flat substrate 2, and a scintillator unit 4 is provided on the semiconductor substrate 3. On the main surface of the semiconductor substrate 3, a light receiving unit 10A in which pixel units _{Pm, n} are arranged, a signal reading unit 20, an AD conversion unit 30, and a control unit 40A are formed and integrated. Bonding pads 50 for input / output and power supply are formed. The scintillator unit 4 is provided so as to cover M × N pixel units P _{1,1 to} P _{M, N} in the light receiving unit 10A. The scintillator unit 4 may be provided on the semiconductor substrate 3 by vapor deposition. Note that each of the signal readout unit 20, the AD conversion unit 30, and the control unit 40A is not integrated on the semiconductor substrate 3 on which the light receiving unit 10A is integrated, and may be integrated on a different semiconductor substrate. It's okay.

FIG. 3 is a circuit diagram of each of the pixel unit P _{m, n} , the integration circuit _Sn, and the holding circuit H _{n of the} solid-state imaging device 1A according to the first embodiment. Here, a circuit diagram of the pixel portion P _{m, n} is shown on behalf of the M × N pixel portions P _{1,1 to} PM _{, N,} and an integration is shown on behalf of the _N integration circuits S _{1 to SN.} It shows a circuit diagram of a circuit _{S n,} also shows a circuit diagram of the holding circuit _{H n} as a representative of the n holding circuits _H 1 to H _n. That is, a circuit portion related to the pixel portion P _{m, n in the m-} th row and the n-th column and the n-th column readout wiring L _{O, n} is shown.

Pixel unit P _{m, n} includes a photodiode PD and a readout switch SW _1. The anode terminal of the photodiode PD is grounded, the cathode terminal of the photodiode PD is connected to the n-th column readout wiring L _O via the readout switch SW _1, and _n. The photodiode PD generates an amount of charge corresponding to the incident light intensity, and accumulates the generated charge in the junction capacitor. Readout switch SW ₁ is the m row selecting wiring L _V, m-th row selection control signal Vsel passed through the _m (m) is given from the control unit 40A. The m-th row selection control signal Vsel (m) instructs the opening / closing operation of the readout switch SW ₁ of each of _{the N} pixel units P _{m, 1 to} P _{m, N} in the m-th row in the light receiving unit 10A. .

The pixel portion P _{m, n,} when the _m-th row selection control signal Vsel (m) is at low level, the readout switch SW ₁ in the open, the charge generated by the photodiode PD, for the n-th column readout Without being output to the wiring L _{O, n} , it is accumulated in the junction capacitance section. On the other hand, when the m-th row selecting control signal Vsel (m) is at high level, closes the readout switch SW _1, the charges accumulated in the junction capacitance portion is generated in the photodiode PD until it is read The signal is output to the n-th column readout wiring L _{O, n} through the switch SW ₁ .

The n-th column readout wiring L _{O, n} is connected to the readout switch SW _{1 of} each of the _M pixel units P _{1, n to} P _{M, n} in the n-th column in the light receiving unit 10A. The n-th column readout wiring L _{O, n} uses the charge generated in the photodiode PD of any one of the _M pixel units P _{1, n to} P _{M, n} to read out the pixel unit. reading via the switch SW _1, transferring to the integrating circuit _{S n.}

The integrating circuit _Sn includes an amplifier A ₂ , an integrating capacitive element C ₂₁ , an integrating capacitive element C ₂₂ , a discharging switch SW ₂₁ and a gain setting switch SW ₂₂ . Integrating capacitive element C ₂₁ and the discharge switch SW ₂₁ is connected in parallel to each other, and provided between an input terminal of the amplifier A ₂ and the output terminal. Moreover, the integrating capacitive element C ₂₂ and the gain setting switch SW ₂₂ is connected in series to each other, the input of the amplifier A ₂ so that the gain setting switch SW ₂₂ is connected to the input terminal side of the amplifier A ₂ It is provided between the terminal and the output terminal. The input terminal of the amplifier A ₂ is connected to the n-th column readout wiring L _{O, n.}

Discharge switch _{SW 21} are reset control signal Reset passing through the resetting wiring _{L R} supplied from the control unit 40A. The reset control signal Reset instructs an opening / closing operation of the discharge switch SW ₂₁ of each of the _N integration circuits S _{1 to} S _N. Gain setting switch SW _22, the gain setting signal Gain is provided passing through the gain setting wiring L _G from the controlling section 40A. The gain setting signal Gain instructs the opening / closing operation of the gain setting switch SW ₂₂ of each of the _N integrating circuits S _{1 to} S _N.

In the integrating circuit _Sn , the integrating capacitive elements C ₂₁ and C ₂₂ and the gain setting switch SW ₂₂ form a feedback capacitive unit having a variable capacitance value. That is, when the gain setting signal Gain is at low level the gain setting switch SW ₂₂ is open, the capacitance value of the feedback capacitance section is equal to the capacitance value of the integrating capacitive element C _21. On the other hand, when the gain setting signal Gain is at a high level and the gain setting switch SW ₂₂ is closed, the capacitance value of the feedback capacitance section is equal to the sum of the capacitance values of the integrating capacitance elements C ₂₁ and C ₂₂ . When the reset control signal Reset is at high level, closes the discharge switch SW _21, the feedback capacitance section is discharged, the voltage output from the integrating circuit S _n is initialized. On the other hand, when the reset control signal Reset is at a low level, the discharge switch SW ₂₁ is opened, the charge input to the input terminal is accumulated in the feedback capacitor unit, and the voltage value corresponding to the accumulated charge amount is an integration circuit. is output from the S _n.

The holding circuit H _n includes an input switch SW ₃₁ , an output switch SW _32, and a holding capacitive element C ₃ . One end of the holding capacitive element C ₃ is grounded. The other end of the holding capacitive element C ₃ is connected via an input switch SW ₃₁ is connected to the output terminal of the integrating circuit S _n, and is connected to the voltage output wiring L _out via the output switch SW _32. Input switch _{SW 31} is supplied with a holding control signal Hold passed through the holding wiring _{L H} from the controlling section 40A. The holding control signal Hold instructs the opening / closing operation of the input switch SW ₃₁ of each of the _N holding circuits H _{1 to} H _N. The output switch SW ₃₂ is supplied with an n-th column selection control signal Hsel (n) that has passed through the n-th column selection wiring L _{H, n} from the control unit 40A. N-th column selecting control signal Hsel (n) is for instructing opening and closing operations of the output switch SW ₃₂ of the holding circuit H _n.

In the holding circuit H _n , when the holding control signal Hold changes from the high level to the low level, the input switch SW ₃₁ changes from the closed state to the opened state, and the voltage value input to the input terminal at that time is held. It is held in the use capacitive element C _3. Further, when the n-th column selection control signal Hsel (n) is at a high level, the output switch SW ₃₂ is closed, and the voltage value held in the holding capacitor C ₃ is supplied to the voltage output wiring L _out . Is output.

When the control unit 40A outputs voltage values corresponding to the light reception intensities of the _N pixel units P _{m, 1 to} P _{m, N} in the m-th row in the light receiving unit 10A, the control unit 40A uses the reset control signal Reset to output N After instructing the switch SW ₂₁ for discharge of each of the integration circuits S _{1 to} S _N to be closed and then opened, the N pixel units in the m-th row in the light receiving unit 10A by the m-th row selection control signal Vsel (m). An instruction is given to close each of the read switches SW ₁ for P _{m, 1 to} P _{m, N} for a predetermined period. During the predetermined period, the control unit 40A instructs the input switches SW ₃₁ of the _N holding circuits H _{1 to} H _N to change from the closed state to the open state by the holding control signal Hold. Then, after the predetermined period, the control unit 40A sequentially sets the output switches SW ₃₂ of each of the _N holding circuits H _{1 to} H _N for a certain period in response to the column selection control signals Hsel (1) to Hsel (N). Instruct to close only. The control unit 40A sequentially performs the above control for each row.

In particular, the solid-state imaging device 1A according to the present embodiment has a first imaging mode and a second imaging mode. The imaging region in the light receiving unit 10A is different between the first imaging mode and the second imaging mode. In the first imaging mode, the control unit 40A sets a voltage value corresponding to the amount of charge generated in each of the M × N pixel units P _{1,1 to} P _{M, N} in the light receiving unit 10A. The signal is output from the signal reading unit 20. The control section 40A, when in the second imaging mode, corresponding to the amount of charge generated in each pixel portion P _{m, n} photodiode PD of which are included in a specific range of M ₁ rows successive in the photodetecting section 10A The voltage value is output from the signal reading unit 20. M ₁ is an integer less than M.

Control section 40A, when in the second imaging mode, as the specific range the scope of _one line M from the row closest counting starting the signal readout section 20 among the M rows in the photodetecting section 10A, each pixel of the specified range It is preferable to output a voltage value corresponding to the amount of charge generated in the photodiode PD of the part P _{m, n} from the signal reading part 20. That is, as shown in FIG. 1, when the row closest to the signal reading unit 20 in the light receiving unit 10A is the first row, the control unit 40A controls the first light receiving unit 10A in the second imaging mode. a range of the above specific range from 1 row to the M ₁ rows, corresponding to the amount of charge generated in each pixel portion P _{m, n} photodiode PD of this specific range (first row to the M ₁ row) The voltage value is preferably output from the signal reading unit 20. In this way, even when the n-th column readout wiring L _{O, n} is disconnected, the photodiodes of the pixel portions P _{m, n in} the specific range are in the second imaging mode. The probability that the voltage value corresponding to the amount of charge generated in the PD can be normally output from the signal reading unit 20 is increased.

The control unit 40A preferably varies the gain, which is the ratio of the output voltage value to the input charge amount in the signal reading unit 20, between the first imaging mode and the second imaging mode. That is, when each integrating circuit S _n as shown in FIG. 3 constituted, the control section 40A, by controlling opening and closing the gain setting switch SW ₂₂ by the gain setting signal Gain, each integrating circuit S _n It is preferable to appropriately set the capacitance value of the feedback capacitance unit so that the gain is different between the first imaging mode and the second imaging mode. In this way, for example, when the number of frame data (frame rate) output from the signal reading unit 20 per unit time differs between the first imaging mode and the second imaging mode, When binning readout is performed in which the data of a plurality of pixel portions are combined into one pixel data in either the mode or the second imaging mode, the pixel data are mutually transferred between the first imaging mode and the second imaging mode. It can be a close value.

For example, when the frame rate is faster in the second imaging mode than in the first imaging mode, or when binning readout is performed in the first imaging mode, the second imaging mode is compared with that in the first imaging mode. It is preferable that the gain in the two imaging mode is large. Therefore, by closing the gain setting switch SW ₂₂ in the first imaging mode, the capacitance value of the feedback capacitor unit is made equal to the sum of the capacitance values of the integrating capacitive element C ₂₁ and the integrating capacitive element C _22. . On the other hand, by opening the gain setting switch SW ₂₂ in the second imaging mode, the capacitance value of the feedback capacitor unit is made equal to the capacitance value of the integrating capacitive element C ₂₁ . In this way, it is possible when in the second imaging mode than when in the first imaging mode, by decreasing the capacitance value of the feedback capacitance section of each integrating circuit S _n, to increase the gain. Thereby, each pixel data can be made into a mutually close value between 1st imaging mode and 2nd imaging mode.

  Next, the operation of the solid-state imaging device 1A according to the first embodiment will be described. In the solid-state imaging device 1A according to the present embodiment, M row selection control signals Vsel (1) to Vsel (M) and N column selection control signals Hsel (1) to Hsel are controlled under the control of the control unit 40A. (N), the reset control signal Reset and the hold control signal Hold each change in level at a predetermined timing, whereby an image of the light incident on the light receiving unit 10A can be taken to obtain frame data.

FIG. 4 is a timing chart for explaining the operation of the solid-state imaging device 1A according to the first embodiment. Here, the operation when binning reading is not performed will be described. This figure shows, in order from the top, (a) N-number of the integrating circuit S ₁ to S _N Reset for instructing respective opening and closing operations of the discharge switches SW ₂₁ control signal Reset, the first row in (b) the light receiving portion 10A the N pixel portions P _{1, 1} to P _{1, N} first row selecting control signal Vsel to instruct the respective opening and closing operation of the readout switch SW ₁ (1), of the second row in (c) light receiving portions 10A N pixel portions P _2,1 to P _{2, N} respective second row selecting control signal Vsel for instructing opening and closing operations of the readout switches SW ₁ (2), and, (d) the N holding circuits H ₁ to H _N holding control signal hold for instructing each of the opening and closing operation of the input switch SW ₃₁ is shown.

Further, in this figure, (e) the first column selection control signal Hsel (1) for instructing the opening / closing operation of the output switch SW ₃₂ of the holding circuit H ₁ and (f) the holding circuit H ₂ in order. second column selection control signal Hsel for instructing opening and closing operations of the output switch _{SW 32 (2), (g} ) the third column selection control signal Hsel for instructing opening and closing operations of the output switch SW ₃₂ of the holding circuit H ₃ (3 ), (h) the n-th column selection control signal Hsel for instructing opening and closing operations of the output switch SW ₃₂ of the holding circuit H _n (n), and, (i) opening and closing operation of the output switch SW ₃₂ of the holding circuit H _n An Nth column selection control signal Hsel (N) is indicated.

Reading of charges generated in the photodiode PD of each of _{the N} pixel parts P _{1,1 to} P _{1, N in} the first row and accumulated in the junction capacitor part is performed as follows. Before the time t _10, M row selecting control signals Vsel (1) ~Vsel (M) , N pieces of column selection control signal Hsel (1) ~Hsel (N) , the reset control signal Reset, and the holding control signal Hold Each is at a low level.

Period from the time _{t 10} to the time _{t 11,} the reset control signal Reset to be output to the reset wiring _{L R} from the controlling section 40A becomes high level, and accordingly, in the N integrating circuits _S 1 to S _N, respectively, the discharge use the switch _{SW 21} closes, the integrating capacitive element _{C 21} is discharged. Further, during a period from the time t ₁₂ after the time t ₁₁ to time t _15, the first row selecting control output from the control unit 40A to the first row selecting wiring L _{V, 1} signal Vsel (1) a high level next, thereby, N pixel units _{P 1, 1} to P of the first row in the photodetecting section 10A _{1, N} the readout switch SW ₁ in each of closed.

Within this period (t _{12 to} t ₁₅ ), during the period from time t ₁₃ to time t ₁₄ , the holding control signal Hold that is output from the control unit 40A to the holding wiring L _H becomes high level. In each of the holding circuits H _{1 to} H _N , the input switch SW ₃₁ is closed.

In the period _(t 12 _{~t 15),} the readout switch SW ₁ in each pixel portion P _{1, n} of the first row is closed, the discharge switch _{SW 21} of each integrating circuit _{S n} is open, The charges that have been generated in the photodiode PD of each pixel part P _{1, n} and accumulated in the junction capacitor part up to that point are the readout switch SW ₁ and the n-th column readout wiring L of the pixel part P _{1, n. O,} and through _n, it is stored after being transferred to the integrating capacitive element C ₂₁ of the integrating circuit S _n. Then, a voltage value corresponding to the amount of charges accumulated in the integrating capacitive element C ₂₁ of each integrating circuit S _n is output from the output terminal of the integrating circuit S _n.

At time _{t 14} in the period _(t 12 _{~t 15)} inside, by holding control signal Hold switches from high level to low level, in the N holding circuits _H 1 to H _N, the input switch _{SW 31} switches from a closed state to an open state, a voltage value being input to the input terminal of the holding circuit H _n are output from the output terminal of the integrating circuit S _n at that time is held in the holding capacitive element C _3.

After the period (t _{12 to} t ₁₅ ), the column selection control signals Hsel (1) to Hsel (N) output from the control unit 40A to the column selection wirings L _{H, 1 to} L _{H, N} are sequentially supplied. The output switch SW _{32 of} each of the _N holding circuits H _{1 to} H _N is sequentially closed for a fixed period and held in the holding capacitor element C ₃ of each holding circuit H _n. The voltage values thus output are sequentially output to the voltage output wiring L _out through the output switch SW ₃₂ . The voltage value V _out output to the voltage output wiring L _out represents the received light intensity in the photodiode PD of each of _{the N} pixel portions P _{1,1 to} P _{1, N} in the first row.

Subsequently, reading of the second row of the N pixel portions P _2,1 to P _{2, N} charges generated in the photodiodes PD accumulated in the junction capacitance portion is performed as follows.

Period from time _{t 20} to the time _{t 21,} the reset control signal Reset to be output to the reset wiring _{L R} from the controlling section 40A becomes high level, and accordingly, in the N integrating circuits _S 1 to S _N, respectively, the discharge use the switch _{SW 21} closes, the integrating capacitive element _{C 21} is discharged. Further, the period from the time t ₂₂ after the time t ₂₁ to time t _25, the second row selection control signal Vsel (2) a high level output from the control unit 40A to the second row selecting wiring L _{V, 2} next, thereby, N pixel units _P of the second row in the photodetecting section 10A _2,1 to P _{2, N} the readout switch SW ₁ in each of closed.

Within this period (t _{22 to} t ₂₅ ), during the period from time t ₂₃ to time t ₂₄ , the holding control signal Hold that is output from the control unit 40A to the holding wiring L _H becomes high level. In each of the holding circuits H _{1 to} H _N , the input switch SW ₃₁ is closed.

After the period (t _{22 to} t ₂₅ ), the column selection control signals Hsel (1) to Hsel (N) output from the control unit 40A to the column selection wirings L _{H, 1 to} L _{H, N} are sequentially supplied. The output switch SW _{32 of} each of the _N holding circuits H _{1 to} H _N is sequentially closed for a certain period. As described above, the voltage value V _out indicating the received light intensity in the second row of the N pixel portions P _2,1 to P _{2, N} respective photodiodes PD is output to the voltage output wiring L _out.

In the first imaging mode, following the operations for the first row and the second row as described above, the same operations from the third row to the M-th row are performed thereafter and obtained by one imaging. Frame data representing an image is obtained. When the operation for the Mth row is completed, the same operation is performed again in the range from the first row to the Mth row, and frame data representing the next image is obtained. In this way, by repeating the same operation at a constant cycle, the voltage value _Vout representing the two-dimensional intensity distribution of the image of the light received by the light receiving unit 10A is output to the voltage output wiring _Lout , and the frame is repeated. Data is obtained.

Note that the solid-state imaging device 1A according to the present embodiment performs an operation shown in FIG. 5 when binning readout is performed in the first imaging mode. FIG. 5 is a timing chart for explaining the operation of the solid-state imaging device 1A according to the first embodiment. This figure shows an operation in the case of binning readout of 2 rows and 2 columns, that is, an operation in the case where the readout pixel pitch in the frame data is set to twice the pitch of the pixel portion. When binning reading is performed, it is preferable that the gain setting switch SW ₂₂ is closed in each integrating circuit _Sn , the capacitance value of the feedback capacitance unit is set to a large value, and the gain is reduced.

  In this figure, in order from the top, (a) reset control signal Reset, (b) first row selection control signal Vsel (1) and second row selection control signal Vsel (2), (c) third row selection control. Signal Vsel (3) and fourth row selection control signal Vsel (4), (d) holding control signal Hold, (e) first column selection control signal Hsel (1), (f) second column selection control signal Hsel ( 2), (g) 3rd column selection control signal Hsel (3), (h) nth column selection control signal Hsel (n), and (i) Nth column selection control signal Hsel (N) are shown. Yes.

If the binning readout of 2 rows and 2 columns, as shown in this figure, during a period from the time t ₁₂ to time t _15, the first to be output from the controlling section 40A to the first row selecting wiring L _{V, 1} row selection control signals Vsel (1) becomes a high level, the first row of the N pixel portions P _{1, 1} to P _{1, N} the readout switch SW ₁ in each of closed in the photodetecting section 10A. Further, in this same period, the control unit 40A second row selection control signal Vsel (2) is at a high level output for the wiring L _{V, 2} second row selection, the second row in the photodetecting section 10A N pixel portions _{P 2,1} to P _{2, N} the readout switch SW ₁ in each of closed.

Thus, the pixel portion P _{1, n} and the pixel portion P _{2, n} charges accumulated in the junction capacitance portion is generated in the respective photodiodes PD are read switch SW ₁ in and the n-th column readout of the pixel units use wiring L _O, through _n, it is stored after being transferred to the integrating capacitive element _{C 21, C 22} of the integrating circuit _{S n.} Then, a voltage value corresponding to the amount of charges accumulated in the integrating capacitive element C _21, C ₂₂ of each integrating circuit S _n is output from the output terminal of the integrating circuit S _n. The operations of the N integrating circuits S _{1 to} S _N and the N holding circuits H _{1 to} H _N are the same as those described above.

The voltage values sequentially output from each of the _N holding circuits H _{1 to} H _N are input to the AD conversion unit 30 and converted into digital values corresponding to the input voltage values. Then, among the N digital values output from the AD conversion unit 30, the digital values corresponding to the first column and the second column are added, and thereafter, every two digital values are added.

Similarly, the period from time t ₂₂ to time t _25, the third row selection control signal Vsel (3) becomes the high level output from the control unit 40A to the third row selecting wiring L _{V, 3,} N pixel portions _P of the third row in the photodetecting section 10A _{3, 1} to P _{3, N} the readout switch SW ₁ in each of closed. Further, in this same period, the control unit 40A fourth row selection control signal Vsel (4) becomes a high level output to the fourth row selecting wiring L _{V, 4,} in the fourth row in the photodetecting section 10A N pixel portions _{P 4, 1} to P _{4, N} the readout switch SW ₁ in each of closed. The signal reading unit 20 and the AD conversion unit 30 perform the same processing. Then, among the N digital values output from the AD conversion unit 30, the digital values corresponding to the first column and the second column are added, and thereafter, every two digital values are added.

  As described above, the light receiving unit 10A simultaneously performs processing for every two rows in order from the first row, and the N digital values output from the AD conversion unit 30 are added in sequence two by two, so that two rows and two columns. Can be read out.

On the other hand, when in the second imaging mode, as described above in the same operation in the range from the first row to the M ₁ rows are performed, frame data representing an image obtained by one imaging is obtained. When the operation is finished for the M _1st row, the same operation is performed again in the range from the 1st row to the M _1st row, and frame data representing the next image is obtained. In this way, by repeating the same operation at a constant cycle, the voltage value _Vout representing the two-dimensional intensity distribution of the image of the light received by the light receiving unit 10A is output to the voltage output wiring _Lout , and the frame is repeated. Data is obtained.

In the second imaging mode, in the range from the (M ₁ +1) -th row to the M-th row, no voltage value is output from the signal reading unit 20 to the voltage output wiring L _out . However, in each pixel unit P _{m, n} in the range from the (M ₁ +1) _-th row to the M-th row, the charges generated by the light incidence on the photodiode PD are accumulated in the junction capacitance portion of the photodiode PD. Eventually, the saturation level of the junction capacitance is exceeded. When the amount of charge accumulated in the junction capacitance portion of the photodiode PD exceeds the saturation level, the charge exceeding the saturation level overflows to the adjacent pixel portion. When neighboring pixel portions is to belong to the M ₁ row, voltage values output from the signal readout section 20 to _the voltage output wiring L _out for the pixel portion of the neighboring becomes inaccurate.

Therefore, it is preferable to provide a discharging means for discharging the junction capacitance portion of the photodiode PD of each pixel portion P _{m, n} in the range from the (M ₁ +1) _-th row to the M-th row in the second imaging mode. It is. The solid-state imaging device 1A according to the present embodiment performs the operation as shown in FIG. 6 in the second imaging mode as such a discharging unit, and from the (M ₁ +1) th row to the Mth row. range each pixel section P _{m of,} by transferring charges accumulated in the junction capacitance portion of the photodiode PD of _n to the integrating circuit S _n, and discharges the junction capacitance portion of the photodiode PD.

FIG. 6 is a timing chart for explaining the operation of the solid-state imaging device 1A according to the first embodiment. This figure shows the operation for the M ₁ row and the (M ₁ +1) rows, respectively, in the second imaging mode.

In this figure, from the top, (a) the reset control signal Reset, (b) the M ₁ row selection control signals _{Vsel (M 1), (c} ) first (M ₁ +1) row selection control signal Vsel (M ₁ +1), (d) holding control signal Hold, (e) first column selection control signal Hsel (1), (f) second column selection control signal Hsel (2), (g) third column selection control signal Hsel (3), (h) nth column selection control signal Hsel (n), and (i) Nth column selection control signal Hsel (N) are shown.

Operation for the M ₁ row in the period from the time t ₄₀ shown in FIG. 6 to time t ₅₀ is the operation for the first row in the period from the time t ₁₀ shown in FIG. 4 to time t ₂₀ It is the same. However, the period from time _{t 42} to time _{t 45,} the _{M 1} row selection control signals Vsel (M ₁₎ becomes high level to be output from the controlling section 40A to the _{M 1} row selection wiring L _{V, M1,} which Accordingly, the _{M 1} row of N pixel units _{P M1,1} to P _{M1, N} the readout switch SW ₁ in each of closed in the photodetecting section 10A.

When in the second imaging mode, when the operation of the first M ₁ row is completed, the time t ₅₀ after the operation of the range from the (M ₁ +1) -th row to the M-th row is performed. That is, the time _{t 50} after the reset control signal Reset to be output to the reset wiring _{L R} from the controlling section 40A becomes high level, and accordingly, in the N integrating circuits _S 1 to S _N, respectively, the discharge switch _{SW 21} Closes. In addition, during the period when the discharge switch SW ₂₁ is closed after time t ₅₀ , the row selection control signals Vsel (M ₁ +1) to Vsel (M) from the (M ₁ +1) th row to the Mth row are high. As a result, the readout switch SW ₁ of each pixel unit P _{m, n} in the range from the (M ₁ +1) _-th row to the M-th row in the light receiving unit 10A is closed.

As described above, when the readout switch SW ₁ of each pixel unit P _{m, n} in the range from the (M ₁ +1) _-th row to the M-th row is closed in the second imaging mode, the photo of the pixel unit is closed. charges accumulated in the junction capacitance of the diode PD is transferred to the integrating circuit S _n, each integrating circuit S by the closing discharge switch SW ₂₁ in _n, the integrating capacitive element C of each integrating circuit S _{n 21} is always in a discharged state. In this way, in the second imaging mode, the junction capacitance part of the photodiode PD of each pixel part P _{m, n} in the range from the (M ₁ +1) th row to the Mth row can be discharged.

At this time, for the range from the (M ₁ +1) th row to the Mth row, the row selection control signals Vsel (M ₁ +1) to Vsel (M) may be sequentially set to the high level. A plurality of row selection control signals among the control signals Vsel (M ₁ +1) to Vsel (M) may be simultaneously at a high level, and the row selection control signals Vsel (M ₁ +1) to Vsel (M ) All at the same time may be high. As described above, in the range from the (M ₁ +1) -th row to the M-th row, a plurality or all of the row selection control signals are simultaneously set to the high level, so that the photodiode PD of each pixel unit P _{m, n} The junction capacitor can be discharged in a shorter time.

By the way, as another imaging mode for outputting data of a small number of pixel units from the signal reading unit 20 as compared with the first imaging mode, each pixel unit P _{m, n} included in the consecutive N ₁ columns in the light receiving unit 10A. It is also conceivable that a voltage value corresponding to the amount of charge generated in the photodiode PD is output from the signal reading unit 20. Here, N ₁ is an integer less than N. However, in this imaging mode in which the data of each pixel unit P _{m, n} in N ₁ columns is output from the signal reading unit 20, the M row selection control signals Vsel from the control unit 40A are obtained in order to obtain one frame data. (1) to Vsel (M) must be output. On the other hand, in the solid-state imaging device 1A according to the present embodiment, one frame data is obtained in the second imaging mode in which data of each pixel unit P _{m, n in} M ₁ rows is output from the signal reading unit 20. Therefore, the control unit 40A of _one M row selection control signals _{Vsel (1) ~Vsel (M 1} ) since it is sufficient to output, it is possible to operate at high speed.

In the timing chart shown in FIGS. 4 to 6 which has been described so far, it initializes the respective integrating circuits S _n after the reading of the voltage value has been completed from the holding circuits H _n. However, as long as it is after the holding by the holding circuit H _n of the output voltage value of each integrating circuit S _n, the period in which the read voltage value from each holding circuit H _n, the integrating circuit a reset control signal Reset to the high level the S _n may be initialized. Thereby, it is possible to operate at higher speed.

  Next, a solid-state imaging device 1B according to the second embodiment will be described. FIG. 7 is a diagram illustrating a configuration of a solid-state imaging device 1B according to the second embodiment. The solid-state imaging device 1B shown in this figure includes a light receiving unit 10B, a signal reading unit 20, an AD conversion unit 30, and a control unit 40B. Further, when used for X-ray detection, a scintillator unit is provided so as to cover the light receiving unit 10B of the solid-state imaging device 1B.

Compared to the configuration of the solid-state image pickup apparatus 1A according to the first embodiment shown in FIG. 1, the solid-state imaging device 1B according to the second embodiment shown in FIG. 7, the wiring L _O for the n-th column _readout, disconnecting switches SW1 _n and the discharge switch SW2 _n is different in that provided on the _n, also different in including a controlling section 40B in place of the control unit 40A.

Switch SW1 _n for each switching away is readout wiring L _O, even on _n, is provided between the first _{M 1} row in the photodetecting section 10B and the _(M 1 +1) rows. That is, when the separation switch SW1 _n is closed, each pixel unit P _{m, n in} the range from the first row to the M-th row is connected to the signal readout unit 20 via the readout wiring L _{O, n.} ing. On the other hand, when the disconnecting switch SW1 _n is open, each pixel unit P _m of the range from the first row to the M _{1 row, n} is readout wiring L _O, a signal readout section 20 via the _n connection However, each pixel unit P _{m, n in} the range from the (M ₁ +1) _-th row to the M-th row is separated from the signal readout unit 20. Each separation switch SW1 _n is connected to the control unit 40B via the separation wiring L _D1, and a separation control signal Disconnect is supplied from the control unit 40B through the separation wiring L _D1 . The disconnect control signal Disconnect instructs the opening / closing operation of each disconnect switch SW1 _n .

Each discharge switch SW2 _n is provided on the read wiring L _{O, n} on a side farther from the signal read unit 20 than the position where the disconnect switch SW1 _n is provided. One end of the discharge switch SW2 _n is connected to each pixel unit P _{m, n} in the range from the (M ₁ +1) _-th row to the M-th row via a read wiring L _{O, n} . The other end of the discharge switch SW2 _n is grounded. Each discharge switch SW2 _n, which is connected to the control unit 40B through the discharge wiring L _D2, the discharge control signal Discharge passed through the discharge wiring L _D2 is given from the control unit 40B. Discharge control signal Discharge is for instructing an opening and closing operation of each discharge switch SW2 _n.

Similar to the control unit 40A in the first embodiment, the control unit 40B outputs the m-th row selection control signal Vsel (m) to the m-th row selection wiring LV _{, m} , and the n-th column selection control signal Hsel ( outputs n) the n-th column selecting wiring L _H, the _n, outputs a discharge control signal Reset to the discharge wiring L _R, outputs a gain setting signal gain to the gain setting wiring L _G, also holding control and it outputs a signal hold to the holding wiring L _H.

In addition, the control unit 40B outputs a disconnect control signal Disconnect to the disconnect wiring L _D1 and supplies the disconnect control signal Disconnect to each of the N disconnect switches SW1 _{1 to} SW1 _N. The control unit 40B, the discharge control signal Discharge is outputted to the discharge wiring _{L D2,} provide the discharge control signal Discharge to each of the N discharge switches _SW2 1 _{~SW2 N.}

The solid-state imaging device 1B according to the second embodiment also has a first imaging mode and a second imaging mode. The imaging region in the light receiving unit 10B is different between the first imaging mode and the second imaging mode. In the first imaging mode, the control unit 40B sets a voltage value according to the amount of charge generated in each of the M × N pixel units P _{1,1 to} P _{M, N} in the light receiving unit 10B. The signal is output from the signal reading unit 20. The control unit 40B, when in the second imaging mode, according to the amount of charge generated in each pixel portion P _{m, n} photodiode PD of the range from the first row in the photodetecting section 10B to the first M ₁ row The output voltage value is output from the signal reading unit 20.

In the solid-state imaging device 1B according to the second embodiment, when in the first imaging mode, disconnection is given through the disconnection wiring L _D1 from the controlling section 40B in the cut away switch SW1 _n control signal Disconnect is a high level Thus, each separation switch SW1 _n is closed. Further, the discharge control signal Discharge provided via a discharge wiring L _D2 from the controlling section 40B to each discharge switch SW2 _n is at low level, the discharge switch SW2 _n opens. In this state, each pixel unit P _{m, n in} the range from the first row to the M-th row is connected to the signal readout unit 20 via the readout wiring L _{O, n} . Then, the same operation as in the first embodiment is performed, and according to the amount of charge generated in each of the M × N pixel portions P _{1,1 to} P _{M, N} in the light receiving portion 10B. The voltage value is output from the signal reading unit 20.

On the other hand, the solid-state imaging device 1B according to the second embodiment, when in the second imaging mode, after the disconnection wiring L _D1 from the controlling section 40B disconnection control signal applied to each switching and disconnecting switch SW1 _n Disconnect the At a low level, each separation switch SW1 _n is opened. Further, the discharge control signal Discharge provided via a discharge wiring L _D2 from the controlling section 40B to each discharge switch SW2 _n is at high level, the discharge switch SW2 _n closes. In this state, each pixel unit P _{m, n in} the range from the first row to the M _1th row is connected to the signal readout unit 20 via the readout wiring L _{O, n} , but the (M ₁ +1) th ) Each pixel portion P _{m, n in} the range from the row to the Mth row is separated from the signal readout portion 20 and grounded.

Then, when in the second imaging mode, for the range from the first row to the M ₁ row, the same operation is performed as in the first embodiment, each pixel portion P _{m, n} photodiode PD A voltage value corresponding to the amount of electric charge generated in the signal is output from the signal reading unit 20. On the other hand, the range from the (M ₁ +1) -th row to the M-th row, the row selection control signals _{Vsel (M 1 +1) ~Vsel (} M) becomes high level, and accordingly, each pixel portion P _{m, n} the cathode terminal of the photodiode PD of, since it is grounded through the switch SW ₁ and the discharge switch SW2 _n for reading each pixel unit P _m, the junction capacitance section of the photodiode PD of _n is discharged. That is, in this case, each discharge switch SW2 _n is connected to the junction capacitance part of the photodiode PD of each pixel part P _{m, n} in the range from the (M ₁ +1) _-th row to the M-th row in the second imaging mode. It acts as a discharge means for discharging.

In the second imaging mode, even if the row selection control signals Vsel (M ₁ +1) to Vsel (M) sequentially become high level for the range from the (M ₁ +1) th row to the Mth row. However, a plurality of row selection control signals among the row selection control signals Vsel (M ₁ +1) to Vsel (M) may be simultaneously at a high level, and the row selection control signal Vsel (M ₁ +1) ) To Vsel (M) may be simultaneously at the high level. As described above, in the range from the (M ₁ +1) -th row to the M-th row, a plurality or all of the row selection control signals are simultaneously set to the high level, so that the photodiode PD of each pixel unit P _{m, n} The junction capacitor can be discharged in a shorter time.

Furthermore, when in the second imaging mode, the pixel unit P _m for the range from the first row to the M _{1 row,} voltage values corresponding to the amount of charges generated in the photodiode PD _n is from the signal readout section 20 The output period and the period in which the junction capacitance portion of the photodiode PD of each pixel unit _{Pm, n} is discharged in the range from the (M ₁ +1) _-th row to the M-th row partially overlap each other. May be. In such a case, higher speed operation is possible.

Further, since the n-th column readout wiring L _{O, n} connected to the signal readout unit 20 is shortened by opening the separation wiring L _D1 in the second imaging mode, noise can be reduced.

  Next, an embodiment of an X-ray inspection system including the solid-state imaging device according to the above embodiment will be described. FIG. 8 is a configuration diagram of the X-ray inspection system 100 according to the present embodiment. An X-ray inspection system 100 according to the present embodiment includes a solid-state imaging device and an X-ray generation device. The X-ray output from the X-ray generation device and transmitted through an inspection object is imaged by the solid-state imaging device. Inspect the object.

  In the X-ray inspection system 100 shown in this figure, the X-ray generator 106 generates X-rays toward a subject (inspection object). The irradiation field of X-rays generated from the X-ray generator 106 is controlled by the primary slit plate 106b. The X-ray generator 106 includes an X-ray tube, and the amount of X-ray irradiation to the subject is controlled by adjusting conditions such as tube voltage, tube current, and energization time of the X-ray tube. The X-ray imager 107 incorporates a CMOS solid-state image pickup device having a plurality of two-dimensionally arranged pixel units, and detects an X-ray image that has passed through the subject. In front of the X-ray imager 107, a secondary slit plate 107a for limiting the X-ray incident area is provided.

  The swivel arm 104 holds the X-ray generator 106 and the X-ray imager 107 so as to face each other and swivels them around the subject during panoramic tomography. In addition, a slide mechanism 113 for linearly displacing the X-ray imager 107 with respect to the subject is provided during linear tomography. The turning arm 104 is driven by an arm motor 110 constituting a rotary table, and the rotation angle is detected by an angle sensor 112. The arm motor 110 is mounted on a movable part of the XY table 114, and the center of rotation is arbitrarily adjusted within a horizontal plane.

  An image signal output from the X-ray imager 107 is converted into, for example, 10-bit (= 1024 level) digital data by the AD converter 120, and once taken in a CPU (Central Processing Unit) 121, the frame memory 122 is then captured. Stored in From the image data stored in the frame memory 122, a tomographic image along an arbitrary tomographic plane is reproduced by a predetermined calculation process. The reproduced tomographic image is output to the video memory 124, converted into an analog signal by the DA converter 125, displayed on the image display unit 126 such as a CRT (cathode ray tube), and used for various diagnoses.

  A work memory 123 necessary for signal processing is connected to the CPU 121, and an operation panel 119 provided with a panel switch, an X-ray irradiation switch, and the like is further connected. The CPU 121 also controls the motor drive circuit 111 that drives the arm motor 110, slit control circuits 115 and 116 that control the opening ranges of the primary slit plate 106b and the secondary slit plate 107a, and the X-ray generator 106. Each is connected to the control circuit 118 and further outputs a clock signal for driving the X-ray imager 107.

  The X-ray control circuit 118 can perform feedback control of the X-ray irradiation amount to the subject based on the signal imaged by the X-ray imager 107.

  In the X-ray inspection system 100 configured as described above, the solid-state imaging device 1A or 1B according to the present embodiment is used as the X-ray imaging device 107.

  The X-ray generator 106 outputs an X-ray at a predetermined divergence angle in the first output mode by controlling the opening range of the slit plate 16b, and the predetermined divergence in the second output mode. X-rays can be output with a divergence angle narrower than the angle. When the X-ray generator 106 outputs X-rays in the first output mode, the X-ray imager 107 that is a solid-state imaging device operates in the first imaging mode. On the other hand, when the X-ray generator 106 outputs X-rays in the second output mode, the X-ray imager 107 that is a solid-state imaging device operates in the second imaging mode.

Here, for example, the first output mode and the first imaging mode correspond to the CT imaging mode described in Patent Document 1, and the second output mode and the second imaging mode are the panorama mode described in Patent Document 1. Or it corresponds to the cephalo mode. The solid-state image pickup device 1A, 1B are arranged perpendicular to the longitudinal direction of the turning plane of the light receiving portion 10A, the imaging in the 10B region (first row to the M ₁ row) when in the second imaging mode .

  Since the X-ray inspection system 100 according to this embodiment includes the solid-state imaging device 1A or 1B according to this embodiment, imaging can be performed at high speed in the second output mode and the second imaging mode.

Assuming that the X-ray inspection system 100 including the solid-state imaging devices 1A and 1B is used for dentistry, the number of columns N is larger than the number of rows M in the light receiving units 10A and 10B of the solid-state imaging devices 1A and 1B. preferable. This is due to the following reasons. That is, in the first imaging mode corresponding to the CT imaging mode, for example, 8 cm or more × 12 cm or more is required as the dimension of the light receiving range used for imaging in the light receiving units 10A and 10B. In the second imaging mode corresponding to the panorama mode, for example, a size of a specific range used for imaging in the light receiving units 10A and 10B is required to be, for example, 15 cm or more × 7 mm or more. Considering that the above-described requirements regarding dimensions are satisfied and that one integrated solid-state imaging device 1A, 1B is most efficiently manufactured from a circular silicon wafer, the shape of the light receiving portions 10A, 10B is one. It must be a long rectangle in the direction. Then, assuming that the light receiving units 10A and 10B must be rectangular, the number N of columns is larger than the number M of rows, and the number M of selection control signals output from the control units 40A and 40B is reduced. To do. Further, it is preferable that the _N holding circuits H _{1 to} H _N in the signal reading unit 20 are divided into a plurality of sets, and an AD conversion unit is individually provided for each set, and these AD conversion units are operated in parallel. . In this way, high-speed reading of pixel data can be realized.

For example, as shown in FIG. 9, the N integration circuits S _{1 to} S _N and the N holding circuits H _{1 to} H _N are divided into four sets, and the integration circuits S _{1 to} S _i and the holding circuit H ₁ are divided. ˜H _i is a first set, integration circuits S _{i + 1 to} S _j and holding circuits H _{i + 1 to} H _j are a second set, integration circuits S _{j + 1 to} S _k and holding circuits H _{j + 1 to} H _k are a third set. In addition, the integration circuits S _{k + 1 to} S _N and the holding circuits H _{k + 1 to} H _N are set as a fourth set. Here, “1 <i <j <k <N”. The AD converter 31 converts the voltage value sequentially output from each of the first set of holding circuits H _{1 to} H _i into a digital value, and sequentially outputs the voltage value from each of the second set of holding circuits H _{i + 1 to} H _j. The converted voltage value is converted into a digital value by the AD conversion unit 32, the voltage value sequentially output from each of the third set of holding circuits H _{j + 1 to} H _k is converted into a digital value by the AD conversion unit 33, The AD converter 34 converts the voltage value sequentially output from each of the fourth set of holding circuits H _{k + 1 to} H _N into a digital value. In addition, AD conversion processing in each of the four AD conversion units 31 to 34 is performed in parallel. In this way, high-speed reading of pixel data can be realized.

For example, in consideration of binning reading of 2 rows and 2 columns, a holding circuit corresponding to an odd number column among _N holding circuits H _{1 to} H _N is set as a first set, and a holding circuit corresponding to an even number column As a second set, it is also preferable that an AD conversion unit is provided for each of the first set and the second set, and these two AD conversion units are operated in parallel. In this case, a voltage value is simultaneously output from the holding circuit corresponding to the odd-numbered column and the holding circuit corresponding to the adjacent even-numbered column, and these two voltage values are simultaneously AD-converted into digital values. . When the binning process is performed, these two digital values are added. In this way, high-speed reading of pixel data can be realized.

DESCRIPTION OF SYMBOLS 1A, 1B ... Solid-state imaging device, 10A, 10B ... Light-receiving part, 20 ... Signal reading part, 30 ... AD conversion part, 40A, 40B ... Control part, P1, _1- PM _{, N} ... Pixel part, PD ... Photo Diode, SW ₁ ... Read switch, SW _{1 1 to} SW _{1 N} ... Disconnect switch, SW 2 _{1 to} SW _{2 N} ... Discharge switch, S _{1 to} S _N ... Integration circuit, C ₂₁ , C ₂₂ ... Capacitance element for integration, SW ₂₁ ... switch for discharge, A ₂ ... amplifier, H _{1 to} H _N ... holding circuit, C ₃ ... holding capacitor, SW ₃₁ ... switch for input, SW ₃₂ ... switch for output, L _{V, m} ... m Row selection wiring, L _{H, n} ... n-th column selection wiring, L _{O, n} ... n-th column readout wiring, L _R ... reset wiring, L _G ... gain setting wiring, L _H ... holding wiring , L _out ... Voltage output wiring.

Claims (5)

An X-ray inspection system that includes a solid-state imaging device and an X-ray generation device, images X-rays output from the X-ray generation device and transmitted through an inspection object, and inspects the inspection object by the solid-state imaging device There,
The solid-state imaging device is
M × N pixel portions P _{1,1 to} P _{M, N} each including M photodiodes, each of which includes a photodiode that generates an amount of charge corresponding to the incident light intensity, and a readout switch connected to the photodiode, are arranged in M rows. A light receiving section arranged two-dimensionally in N rows;
The light receiving unit is connected to a readout switch for each of the _M pixel units P _{1, n to} P _{M, n} in the n-th column, and any one of the _M pixel units P _{1, n to} P _{M, n} A readout wiring L _{O, n} for reading out the charge generated in the photodiode of the pixel portion via the readout switch of the pixel portion;
Connected to each of the read wirings L _{O, 1 to} L _{O, N} , holds a voltage value corresponding to the amount of charge input through the read wiring L _{O, n} , and sequentially holds the held voltage values. A signal readout unit for outputting to
The light receiving unit controls the open / close operation of the readout switches of the M × N pixel units P _{1,1 to} P _{M, N} and also controls the voltage value output operation of the signal readout unit to A control unit that outputs a voltage value corresponding to the amount of charge generated in each of the photodiodes of the M × N pixel units P _{1,1 to} P _{M, N in the} unit from the signal reading unit;
With
The control unit is
In the first imaging mode, a voltage value corresponding to the amount of charge generated in each of the M × N pixel units P _{1,1 to} P _{M, N} in the light receiving unit is output from the signal reading unit. Let
In the second imaging mode, a voltage value corresponding to the amount of electric charge generated in the photodiode of each pixel unit P _{m, n} included in a specific range of consecutive M ₁ rows in the light receiving unit is output from the signal reading unit. Output
The solid-state imaging device and the X-ray generation device can turn around the inspection object in a state where they face each other, or the solid-state imaging device can be linearly displaced with respect to the inspection object, It is arranged so that the longitudinal direction of the specific range in the light receiving unit in the second imaging mode is perpendicular to the moving direction of the solid-state imaging device at the time of turning or linear displacement ,
The signal readout section is connected to each of the readout wirings L _{O, 1 to} L _{O, N on one} side of the specific range ,
On the other side of the specific range, each of the readout wirings L _{O, 1 to} L _{O, N} is provided with a discharge switch for discharging the junction capacitance portion of the photodiode of each pixel portion.
X-ray inspection system, characterized in that (however, M, N is an integer of 2 or more, M ₁ is less than M integers, m is an integer of 1 to M, n represents 1 or more N an integer). Wherein the control unit is, when the second imaging mode, as the specific range range of _one line M counted in order from the row closest to the signal readout section among the M rows in the light receiving portion, each of the specific range 2. The X-ray inspection system according to claim 1, wherein a voltage value corresponding to an amount of electric charges generated in a photodiode of the pixel unit P _{m, n} is output from the signal reading unit. A separation switch provided on each readout wiring L _{O, n} between the specific range in the light receiving unit and another range excluding the specific range;
The control unit closes the separation switch when in the first imaging mode, and opens the separation switch when in the second imaging mode;
The X-ray inspection system according to claim 2.   2. The control unit according to claim 1, wherein a gain that is a ratio of an output voltage value to an input charge amount in the signal readout unit is different between the first imaging mode and the second imaging mode. X-ray inspection system. 5. The X according to claim 1, further comprising a scintillator portion provided so as to cover M × N pixel portions P _{1,1 to} P _{M, N} in the light receiving portion. Line inspection system.

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