JP2010171487A - Imaging apparatus and portable radiographic image photographing apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an imaging apparatus capable of achieving refresh free in writing image data in a DRAM. <P>SOLUTION: The imaging apparatus 1 includes a plurality of imaging elements 7 which are two-dimensionally arrayed; the DRAM 42 for storing image data of the imaging elements 7; and a memory controller 43 for controlling the writing/reading of image data in/from the DRAM 42. The memory controller 43 controls writing such that image data of each line Lx of scanning lines 5 are written over a plurality of rows of the DRAM 42 so that the number of data written in each row (rowz) becomes a part of a quotient obtained by equally dividing the number of columns per row and the image data of one scanning line 5 are not written in the same plurality of rows as the image data of another line Lx at least adjacent to the line Lx concerned, and controls the time interval ΔT of writing operation in respective rows (rowz) of the DRAM 42 within the data holding time of the DRAM. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an imaging device and a portable radiographic imaging device.

  For the purpose of disease diagnosis and the like, radiographic images taken using radiation typified by X-ray images are widely used. Conventionally, such medical radiographic images have been taken using a screen film, but recently, in order to digitize radiographic images, irradiated radiation is detected by an image sensor and acquired as digital image data. Radiographic imaging devices have been developed.

  Such a type of radiographic imaging apparatus is known as an FPD (Flat Panel Detector). In the FPD, usually, a detection unit is formed by arranging a plurality of imaging elements in a two-dimensional array on the surface of a substrate or the like. Then, the irradiated radiation is converted into image data by a radiation detection element that is an imaging device (so-called direct type), or the irradiated radiation is once converted into light of another wavelength such as visible light by a scintillator or the like and converted The irradiated light is converted into image data by a photoelectric conversion element that is an image sensor (so-called indirect type), and the radiation irradiated to the FPD through the subject is converted into image data corresponding to the dose. (See, for example, Patent Document 1).

  Furthermore, in recent years, a portable radiographic imaging device that has been made portable by, for example, housing a detection unit in which a plurality of imaging elements are arranged in a two-dimensional manner in a housing has been developed and put into practical use (for example, (See Patent Document 2 etc.).

  In addition to the FPD, an imaging device such as a digital camera is known as one that converts light incident on a plurality of detection elements arranged two-dimensionally into the detection unit into image data in this way (for example, (See Patent Document 3). For example, in a digital camera, an optical sensor such as a CCD (Charge Coupled Device) or a CMOS (Complementary Metal Oxide Semiconductor) is arranged in a two-dimensional manner as an image sensor, and incident visible light is converted into image data.

  An imaging device such as a radiographic imaging device or a digital camera that converts radiation and visible light incident on a plurality of imaging elements arranged in a two-dimensional manner into a detection unit into digital image data and detects it. That's it. Further, hereinafter, the term “light” refers to light in a wavelength region including not only visible light but also radiation.

  In these imaging apparatuses, the obtained image data is temporarily stored in a storage means provided in the apparatus, and after shooting, the image data is stored in another storage medium, or taken out to an external apparatus and its monitor screen is displayed. Processing such as displaying above or recording and outputting on an image recording medium such as a film is performed. As a storage means, a DRAM (Dynamic Random Access Memory) having advantages such as a simple circuit configuration and an easy integration can be used as compared with an SRAM (Static Random Access Memory).

  Here, as shown in FIG. 12, x (line) × y (column) imaging elements 101 are two-dimensionally arranged on the detection unit 100, and the DRAM is z (row, row) × w. It is assumed that a memory area of (column) is provided.

  In actual specifications, the line number and column number of the image sensor, the row address and column address of the DRAM are usually represented by numbers starting from 0. However, in the following, for convenience, the line number x, the column number y, and the row address are represented. The number z and the column number w are represented by numbers starting from 1, such as 1, 2, 3,. Each image sensor may be represented as an image sensor (x, y) using a line number x and a column number y.

  When image data is read from the image sensor 101 of the detection unit 100, each image data of each image sensor 101 of the line 1 (that is, x = 1) is normally read sequentially from the image sensor (1, 1), and the image of the line 1 is imaged. When all the reading of the element (1, y) is completed, the image data is read sequentially from the imaging element (2, 1) of the line 2, and the line number x is sequentially incremented from each imaging element 101. Read image data. Conversely, image data may be read while sequentially starting to read out image data from each image sensor 101 of the last line and sequentially decrementing the line number.

  Then, as shown in FIG. 12, for example, when each image data is read out from each image sensor 101 of 1024 (line) × 1024 (column) and stored in the DRAM 102 of 2048 (row) × 512 (column), for example, Each image data is written in such a manner that the image data of 1024 image sensors 101 for one line is written in a memory area (that is, 512 × 2) for two rows (rows) of the DRAM 102.

JP-A-9-73144 JP-A-6-342099 JP 2002-281430 A

  By the way, when a DRAM is used as the storage means, as is well known, a refresh operation for holding data is required. When writing to or reading from the DRAM, data is held for each target row by a write operation or a read operation. Therefore, at least for the row, if a write operation or a read operation is performed within the data retention time after a refresh operation or the like is performed, it is not necessary to perform a refresh operation again for data retention.

  That is, in the example of FIG. 12 described above, when each image data is written to the DRAM 102, the image data of each image sensor 101 for one line of the detection unit 100 is read and written to two rows of the DRAM 102. Therefore, the refresh operation need not be performed for the two rows. For the two rows, since the writing operation is not performed at least during the reading period of the image data from each image sensor 101 of the detection unit 100 at this time, a periodic refresh operation is performed within the data holding time. It will be necessary to resume.

  As described above, when a DRAM is used as the storage unit, due to the above-described characteristics of the DRAM, when image data is written to the DRAM from each imaging element of the detection unit of the imaging device, or when image data is read from the DRAM. Since the refresh operation is not necessary, the power consumed correspondingly is reduced.

  In the imaging device, not only in the case of a digital camera but also in the radiographic imaging device, especially in the portable radiographic imaging device, a battery is usually built in, and as much power as possible is used to prevent the battery from being consumed. It is required to be configured to avoid consumption.

  For this reason, in such an imaging apparatus, the refresh operation is not performed at least when writing image data from the detection unit to the DRAM or reading image data from the DRAM by utilizing the characteristics of the DRAM (that is, It is desirable to configure the imaging device so as to realize so-called refresh-free.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide an imaging apparatus and a portable radiographic imaging apparatus capable of realizing refresh-free when image data is written to or read from a DRAM. To do.

In order to solve the above-described problem, the imaging apparatus of the present invention
A plurality of image sensors that are provided in each region partitioned by a plurality of scanning lines and a plurality of signal lines arranged so as to cross each other and generate electric charges according to the amount of irradiated light are two-dimensional Detectors arranged in a shape,
A scanning drive circuit for sequentially switching the lines of the scanning lines to which a signal readout voltage is applied;
A switching element connected to each of the scanning lines and for discharging the charge accumulated in the imaging element to the signal line when the voltage for signal readout is applied;
A readout circuit that reads out the electric charge from the imaging device via the signal line and sequentially outputs image data for each imaging device;
DRAM in which image data for each image sensor is stored in a predetermined memory area;
A memory controller for controlling writing of the image data to the DRAM and reading of the image data from the DRAM;
With
The memory controller spans the image data for each line of the scanning line across a plurality of rows in the predetermined memory area of the DRAM, and the number of data written for each row is the number of columns per row. The image data for one line of the scanning line is at least the same as the image data of the other lines adjacent to the line in the detection unit. And the time interval of the write operation to each row in the predetermined memory area of the DRAM is controlled to be within the data holding time of the DRAM.

  Moreover, the portable radiographic imaging device of this invention has the structure of the said imaging device of this invention, The said imaging device of the said detection part was the radiation detection element which detects the irradiated radiation, or irradiated It is a photoelectric conversion element that detects light in which radiation is converted to another wavelength.

  According to the imaging apparatus and the portable radiographic imaging apparatus of the present invention, the control is performed so that the time interval of the write operation to each row of the DRAM is within the data holding time of the DRAM. During the period of writing image data from the image sensor to the DRAM, it is not necessary to perform a refresh operation. Therefore, it is possible to reduce the power consumed by that amount.

  As described above, in addition to the case where the imaging device is a digital camera, in particular, the portable radiographic imaging device may be configured to avoid as much useless power consumption as possible in order to prevent the built-in battery from being consumed. Although requested, according to the portable radiographic imaging apparatus of the system of the present invention, it is possible to realize refresh-free at least in the operation of writing image data to the DRAM as described above. As a result, it is possible to reduce the amount of power consumed, and to effectively prevent the internal battery from being consumed.

It is a perspective view which shows the radiographic imaging apparatus which concerns on this embodiment. It is sectional drawing which follows the AA line in FIG. It is a top view which shows the structure of the board | substrate which concerns on this embodiment. FIG. 4 is an enlarged view showing a configuration of an imaging element, a thin film transistor, and the like formed in a small region on the substrate of FIG. 3. It is sectional drawing which follows the XX line in FIG. It is a side view explaining the board | substrate with which COF, a PCB board | substrate, etc. were attached. It is a figure showing the equivalent circuit schematic of the radiographic imaging apparatus which concerns on this embodiment. It is a figure explaining writing to DRAM of image data of line L1 of a scanning line in this embodiment. It is a figure explaining writing to DRAM of image data of line L2 of a scanning line in this embodiment. It is a figure explaining writing to DRAM of image data of line L8 of a scanning line in this embodiment. It is a figure explaining writing to DRAM of image data of line L9 of a scanning line in this embodiment. It is a figure explaining the structure of DRAM and the writing of the image data of each line of the conventional scanning line to DRAM.

  Embodiments of an imaging apparatus and a portable radiographic imaging apparatus according to the present invention will be described below with reference to the drawings. However, the present invention is not limited to the following illustrated examples.

  Hereinafter, a case where the imaging device is a portable radiographic imaging device will be described. Also, as a portable radiographic image capturing device, a scintillator or the like is provided, and the emitted radiation is converted into light of other wavelengths such as visible light by the scintillator, and an electric signal is output by a photoelectric conversion element such as a photodiode as an imaging element. A so-called indirect portable radiographic image capturing apparatus will be described. The present invention relates to a so-called direct portable radiographic image capturing apparatus in which radiation is directly detected by a radiation detecting element that is an imaging element without using a scintillator or the like. It can also be applied to.

  The present invention is not limited to the case where the imaging device is a portable radiographic imaging device, and as described above, the imaging device such as a digital camera provided with an optical sensor such as a CCD or CMOS as an imaging device. Also applies. Hereinafter, for convenience, the portable radiographic imaging device is simply referred to as a radiographic imaging device.

  FIG. 1 is an external perspective view of the radiographic image capturing apparatus according to the present embodiment, and FIG. 2 is a cross-sectional view taken along line AA in FIG. The radiographic imaging apparatus 1 according to the present embodiment is a cassette-type portable radiographic imaging apparatus in which a scintillator 3, a substrate 4, and the like are housed in a housing 2 as shown in FIGS. 1 and 2. It is configured.

  The housing 2 is formed of a material such as a carbon plate or plastic that transmits radiation at least on a surface R (hereinafter referred to as a radiation incident surface R) that receives radiation. 1 and 2 show a case where the housing 2 is a so-called lunch box type formed by the frame plate 2A and the back plate 2B. However, the housing 2 is integrally formed, so-called monocoque. It can also be a type.

  As shown in FIG. 2, a base 31 is disposed on the lower side of the substrate 4 inside the housing 2, and the base 31 includes a PCB substrate 33 on which electronic components 32 and the like are disposed, and a buffer member. 34 etc. are attached. In the present embodiment, a glass substrate 35 for protecting the substrate 4 and the scintillator 3 on the radiation incident surface R side is disposed.

  The scintillator 3 is, for example, one that has a phosphor as a main component and converts the light into a light having a wavelength of 300 to 800 nm when receiving radiation, that is, a light centered on visible light and outputs the light. The scintillator 3 is attached to a detection unit P, which will be described later, of the substrate 4.

  In the present embodiment, the substrate 4 is formed of a glass substrate. As shown in FIG. 3, a plurality of scanning lines 5 and a plurality of signal lines are provided on a surface 4 a of the substrate 4 facing the scintillator 3. 6 are arranged so as to cross each other. In each small region r defined by the plurality of scanning lines 5 and the plurality of signal lines 6 on the surface 4 a of the substrate 4, an image sensor 7 made of a photodiode or the like is provided. As described above, the image pickup devices 7 are two-dimensionally arranged on the substrate 4, and the entire region r in which the plurality of image pickup devices 7 are provided, that is, the region indicated by the alternate long and short dash line in FIG. Has been.

  In the present embodiment, as the imaging device 7, the radiation incident from the radiation incident surface R is converted by the scintillator 3 and output according to the amount of light output (varies according to the radiation dose incident on the scintillator 3). Although a photodiode for generating electric charge is used, for example, a phototransistor or the like can also be used. Each imaging element 7 is connected to a source electrode 8s of a TFT (Thin Film Transistor) 8 as a switching element, as shown in the enlarged views of FIGS. The drain electrode 8 d of the TFT 8 is connected to the signal line 6.

  The TFT 8 is configured to discharge the electric charge accumulated in the image pickup device 7 to the signal line 6 by applying a signal readout voltage to the gate electrode 8g and being turned on. Here, the structure of the image sensor 7 and the TFT 8 in this embodiment will be briefly described with reference to a cross-sectional view shown in FIG. FIG. 5 is a sectional view taken along line XX in FIG.

A gate electrode 8g of a TFT 8 made of Al, Cr or the like is formed on the surface 4a of the substrate 4 so as to be integrally laminated with the scanning line 5, and silicon nitride (laminated on the gate electrode 8g and the surface 4a). An upper portion of the gate electrode 8g on the gate insulating layer 81 made of SiN _x ) or the like is connected to the first electrode 74 of the image sensor 7 via a semiconductor layer 82 made of hydrogenated amorphous silicon (a-Si) or the like. The source electrode 8s and the drain electrode 8d formed integrally with the signal line 6 are laminated.

The source electrode 8s and the drain electrode 8d are divided by a first passivation layer 83 made of silicon nitride (SiN _x ) or the like, and the first passivation layer 83 covers both the electrodes 8s and 8d from above. In addition, ohmic contact layers 84a and 84b formed in an n-type by doping hydrogenated amorphous silicon with a group VI element are stacked between the semiconductor layer 82 and the source electrode 8s and the drain electrode 8d, respectively. The TFT 8 is formed as described above.

  In the image pickup device 7, an auxiliary electrode 72 is formed by laminating Al, Cr, or the like on the insulating layer 71 formed integrally with the gate insulating layer 81 on the surface 4 a of the substrate 4. A first electrode 74 made of Al, Cr, Mo or the like is laminated on the auxiliary electrode 72 with an insulating layer 73 formed integrally with the first passivation layer 83 interposed therebetween. The first electrode 74 is connected to the source electrode 8 s of the TFT 8 through the hole H formed in the first passivation layer 83.

  On the first electrode 74, an n layer 75 formed in an n-type by doping a hydrogenated amorphous silicon with a group VI element, an i layer 76 which is a conversion layer formed of hydrogenated amorphous silicon, and a hydrogenated amorphous A p layer 77 formed by doping a group III element into silicon and forming a p-type layer is formed by laminating sequentially from below. The order of stacking the p layer 77, the i layer 76, and the n layer 75 may be reversed.

  On the p layer 77, a second electrode 78 made of a transparent electrode such as ITO is laminated and formed so that irradiated light reaches the i layer 76 and the like. The image sensor 7 is formed as described above. In the present embodiment, as described above, the case where a so-called pin-type image sensor formed by stacking the p layer 77, the i layer 76, and the n layer 75 is used as the image sensor 7 has been described. 7 is not limited to such a pin-type imaging device.

A bias line 9 that applies a reverse bias voltage to the image sensor 7 is connected to the upper surface of the second electrode 78 of the image sensor 7 via the second electrode 78. Note that the second electrode 78 and the bias line 9 of the image sensor 7, the first electrode 74 extended to the TFT 8 side, the first passivation layer 83 of the TFT 8, that is, the upper surfaces of the image sensor 7 and the TFT 8 are on the upper side. Is covered with a second passivation layer 79 made of silicon nitride (SiN _x ) or the like.

  As shown in FIG. 3 and FIG. 4, in this embodiment, one bias line 9 is connected to a plurality of imaging elements 7 arranged in a row, and each bias line 9 is connected to a signal line 6. They are arranged in parallel. In addition, each bias line 9 is bound to one connection 10 at a position outside the detection portion P of the substrate 4.

  In the present embodiment, the connection lines 10 of the scanning lines 5, the signal lines 6, and the bias lines 9 are respectively connected to input / output terminals (also referred to as pads) 11 provided near the edge of the substrate 4. As shown in FIG. 6, a COF (Chip On Film) 12 in which a chip such as an IC 12a is incorporated in each input / output terminal 11 is an anisotropic conductive adhesive film (Anisotropic Conductive Film) or anisotropic conductive paste (Anisotropic paste). It is connected via an anisotropic conductive adhesive material 13 such as Conductive Paste).

  The COF 12 is routed to the back surface 4b side of the substrate 4 and connected to the PCB substrate 33 described above on the back surface 4b side. Thus, the board | substrate 4 part of the radiographic imaging apparatus 1 is formed.

  On the other hand, as shown in FIG. 1, a power switch 36 of the radiographic image capturing apparatus 1, indicators 37 for displaying various operation statuses, and the like are provided on the side surface of the short side on one side of the housing 2. In addition, a cover member 38 for replacing an internal battery (not shown) is provided on the side surface portion, and the radiographic image capturing apparatus 1 transmits and receives data, signals, and the like with an external device in a wireless manner on the cover member 38. An antenna device 39 for performing is embedded and provided.

  Here, the circuit configuration of the radiation image capturing apparatus 1 will be described. FIG. 7 is an equivalent circuit diagram of the radiation image capturing apparatus 1 according to the present embodiment.

  As described above, each imaging element 7 of the detection unit P of the substrate 4 has the second electrode 78 connected to the bias line 9 and the connection 10, respectively, and the connection 10 is connected to the reverse bias power supply 14. The reverse bias power supply 14 supplies a reverse bias voltage to be applied to each image sensor 7 via the connection 10 and each bias line 9. The reverse bias power supply 14 is connected to the control means 22, and the control means 22 controls the reverse bias voltage applied to each image sensor 7 from the reverse bias power supply 14.

  The first electrode 74 of each imaging element 7 is connected to the source electrode 8s (denoted as S in FIG. 7) of the TFT 8, and the gate electrode 8g (denoted as G in FIG. 7) of each TFT 8. Are connected to the lines L1 to Lx of the scanning line 5 extending from the scanning drive circuit 15, respectively. Further, the drain electrode 8 d (denoted as D in FIG. 7) of each TFT 8 is connected to each signal line 6.

  When a signal reading voltage is applied from the scanning drive circuit 15 to the gate electrode 8g of the TFT 8 via the lines L1 to Lx of the scanning line 5, the TFT 8 serving as a switch element is turned on, and the imaging element 7 is turned on. The accumulated charges are read from the drain electrode 8d to the signal line 6 through the source electrode 8s of the TFT 8.

  Each signal line 6 is connected to each readout circuit 17 formed in the readout IC 16. Note that a predetermined number of readout circuits 17 are provided in the readout IC 16, and by providing a plurality of readout ICs 16, readout circuits 17 corresponding to the number of signal lines 6 are provided.

  Note that the subscript x representing the line Lx of the scanning line 5 corresponds to the line number x of each image sensor 101 shown in FIG. Further, in FIG. 7, each image sensor 7 connected to each signal line 6 via the TFT 8 corresponds to the image sensor 7 of the same column number y in FIG.

  The readout circuit 17 includes an amplifier circuit 18, a correlated double sampling circuit 19, an analog multiplexer 21, and an A / D converter 20. In the readout circuit 17, charges are read from the image sensor 7 through the signal line 6, and the charges are converted into electric signals by charge-voltage conversion and amplification for each image sensor 7.

  Then, the electrical signal that has been subjected to charge-voltage conversion and output is transmitted to the analog multiplexer 21, sequentially transmitted from the analog multiplexer 21 to the A / D converter 20, and sequentially converted into digital image data by the A / D converter 20. Then, it is output to the DRAM 42 described later. In FIG. 7, the correlated double sampling circuit 19 is denoted as CDS.

  The control means 22 is composed of a microcomputer equipped with a CPU (Central Processing Unit) or the like or a dedicated control circuit, and controls the operation of each member of the radiographic image capturing apparatus 1.

  As described above, the control means 22 controls the reverse bias power supply 14 to control the reverse bias voltage applied to each image sensor 7 or scan the line Lx of the scanning line 5 to which the signal reading voltage is applied. A signal for instructing the start of the signal is transmitted to the scanning drive circuit 15 or the amplification circuit 18 and the correlated double sampling circuit 19 in each readout circuit 17 are controlled to read out the electrical signal from each image sensor 7. Is supposed to do.

  The control unit 22 is connected to the antenna device 39 described above, and further supplies power to each member such as the detection unit P, the scanning drive circuit 15, the readout circuit 17, or the DRAM 42 and the memory controller 43 described later. A battery 40 is connected. As described above, the battery 40 is built in the housing 2 of the radiographic image capturing apparatus 1, and the battery 40 has a connection terminal 41 when the battery 40 is charged by supplying power from the external device to the battery 40. It is attached.

  Further, in the control means 22, the DRAM 42 in which image data for each image sensor 7 is written, and the image data for each image sensor 7 sequentially output from the A / D converter 20 as described above are written into the DRAM 42. A memory controller 43 that controls reading of each image data from the DRAM 42 is connected.

  As the DRAM 42, as shown in FIG. 12, a known DRAM having a memory area of z (row) × w (column) is used. The type of the DRAM 42 is not particularly limited, and a DRAM such as an asynchronous DRAM, SDRAM (Synchronous DRAM), EDO DRAM (Extended Data Output DRAM) or the like is appropriately selected and used.

  Here, before describing the writing of image data of each image sensor 7 to the DRAM 42, etc., generation of charges in the image sensor 7 due to irradiation of radiation and reading processing of image data from the image sensor 7 will be described. .

  Radiation imaging is performed by irradiating the radiation imaging apparatus 1 with radiation in a state where the application of voltage for signal readout from the scanning drive circuit 15 to all the scanning lines 5 is stopped, each TFT 8 is turned off, and the gate is closed. When performed, the irradiated radiation enters the scintillator 3 (see FIG. 2), and the scintillator 3 converts the radiation into light of another wavelength, and the light enters the imaging element 7 below the radiation.

  When light enters the image sensor 7 and reaches the i layer 76 (see FIG. 5) of the image sensor 7, an electron-hole pair is generated in the i layer 76 and formed in the image sensor 7 by applying a reverse bias voltage. According to the predetermined potential gradient, one of the generated electrons and holes (holes in this embodiment) flows out to the bias line 9, and the other charge (electrons in this embodiment) flows into the image sensor 7. Accumulated within.

  When radiation image capturing is completed and radiation irradiation is stopped, a signal for starting reading of image data from each image sensor 7 is transmitted from the control means 22 to the scanning drive circuit 15. When receiving the signal, the scanning drive circuit 15 first applies a signal readout voltage to the line L <b> 1 of the predetermined scanning line 5. The TFT 8 connected to the line L1 of the scanning line 5 to which the voltage for signal readout is applied is turned on, and the electric charge accumulated in each imaging element 7 is released to the signal line 6 through the TFT 8.

  Then, the electric charge discharged from the image pickup device 7 to the signal line 6 is converted into an electric signal by being subjected to charge-voltage conversion and amplification in the readout circuit 17, and sequentially converted into an A / D converter 20 via the analog multiplexer 21. Are converted into digital image data and output to the DRAM 42.

  Then, when the scanning drive circuit 15 stops the application of the signal reading voltage to the line L1 of the scanning line 5 and switches the scanning line 5 to which the signal reading voltage is applied to the next line L2, the scanning line 5 The charge accumulated in the same manner as described above is discharged from each image sensor 7 connected to the line L2 via the TFT 8 to the signal line 6, and the charge is converted into a charge voltage by the readout circuit 17 and amplified. The image data is converted to image data, and each image data is output to the DRAM 42.

  In this way, the scanning drive circuit 15 sequentially switches (that is, scans) the line Lx of the scanning line 5 to which the signal reading voltage is applied, and the image data is read from each image sensor 7 and output to the DRAM 42. Thus, a process for reading image data from all the image sensors 7 is performed.

  As described above, when the image data of each image sensor 7 is sequentially output to the DRAM 42 for each line Lx of the scanning line 5, the memory controller 43 designates a row address or a column address for the DRAM 42. The image data is controlled to be written in the DRAM 42 by a preset procedure.

  The image data is written in a predetermined memory area of the DRAM 42. The predetermined memory area can be set in the entire memory area of the DRAM 42 or a part thereof, and is set as appropriate in advance. The following description such as writing to the DRAM 42 means writing to a predetermined memory area set in the DRAM 42.

  Hereinafter, the image data writing control by the memory controller 43 will be described, and the operation of the radiation image capturing apparatus 1 according to the present embodiment will be described.

  In the present invention, the image data of each image sensor 7 output for each line Lx of the scanning line 5 is written in a predetermined small area of the DRAM 42, and the image data is written for each line Lx of the scanning line 4. The row address is switched so that the region is located at a different position in the row direction of the DRAM 42.

  Specifically, when the image data of each imaging device 7 of the line L1 of the scanning line 5 is transmitted to the DRAM 42, the memory controller 43 converts the image data into, for example, the row of the DRAM 42 as shown in FIG. Write to the small areas of row1 to row256 and columns column1 to column4.

  That is, among the image data of each imaging device 7 of the line L1 of the scanning line 5, the image data with column numbers y of 1 to 4 is written into the columns column1 to column4 of the row 1 of the DRAM 42, and then the column number y is 5 The image data of .about.8 are written in the columns column1 to column4 of the row 2 of the DRAM 42 so that the image data of the image pickup devices 7 whose column numbers y of the scanning lines 5 are 1 to 1024 are stored in the row 1 of the DRAM 42. Write to a small area of ~ row256 and columns column1 to column4.

  Further, as shown in FIG. 9, when the image data of each imaging device 7 of the line L2 of the scanning line 5 is transmitted to the DRAM 42, the memory controller 43 writes the row data 1 of the DRAM 42 in which the image data of the line L1 is written. For example, the data is written in the small regions of the row regions 257 to 512 and columns column 1 to column 4 which are different from the small regions of .about.256.

  As described above, the memory controller 43 extends the image data for each line Lx of the scanning line 5 across a plurality of rows of the DRAM 42 and the number of data written for each row rowz is the number of columns per row (FIG. 8). Or 512 columns in the case of FIG. 9) to be a part of each part (N is a natural number of 2 or more) divided into each part (each part of 4 columns divided into 128 parts in the case of FIG. 8 and FIG. 9). It comes to write.

  Moreover, the memory controller 43 has a plurality of rows in which the image data of one line (for example, the line L2) of the scanning line 5 is at least the same as the image data of other lines (for example, the line L1) adjacent to the line in the detection unit P. Control is performed so as not to write to (for example, row 1 to row 256).

  When controlled in this way, for example, at the read timing of the image data from each image sensor 7 of the line L1 of the scan line 5, when each image data of the line L1 is written to the DRAM 42, the rows 1 to 256 are accessed and scanned. At the read timing of the image data from the image pickup devices 7 of the line L2 of the line 5, when the image data of the line L2 is written into the DRAM 42, the rows 257 to 512 are accessed.

  As described above, by performing the write control as described above, a plurality of different rows (for example, 256 rows) of the DRAM 42 are generated at each read timing of the image data from each imaging device 7 of each line Lx of the scanning line 5. Each can be configured to be accessed.

  In the present embodiment, as described above, the memory controller 43 is adjacent in the row direction of a small area of 256 (row) × 4 (column) on the DRAM 42 in which, for example, the image data of the line L1 of the scanning line 5 is written. The image data of the line L2 of the scanning line 5 is written in a small area of 256 (row) × 4 (column), and the image data of the lines L3, L4,. ) × 4 (column) small areas.

  Then, as shown in FIG. 10, the image data of the line L8 of the scanning line 5 is read out, and the image data is written in the small regions of the row row 1793 to row 2048 and the columns column 1 to column 4 of the DRAM 42. When the first writing to all the rows row1 to row 2048 (in a predetermined memory area) is completed, in the present embodiment, the memory controller 43 uses the column columns 5 to 5 adjacent thereto in the same order as the first writing order. Subsequent to column 8, image data of each subsequent line Lx is written.

  Specifically, as shown in FIG. 11, when the image data of each imaging device 7 of the line L9 of the scanning line 5 is transmitted to the DRAM 42, the memory controller 43 converts the image data to the row rows1 to 1 of the DRAM 42. Write to the small areas of row 256 and columns column 5 to column 8, and illustration is omitted, but thereafter, the transmitted image data of lines L 10, L 11,... of scanning line 5 is 256 (row) × 4 adjacent in the row direction. Write sequentially to small areas in (column).

  Then, the image data of the line L16 of the scanning line 5 is read out, and the image data is written in the small regions of the rows row 1793 to row 2048 and the columns column 5 to column 8 of the DRAM 42, and all the rows row 1 to row 2048 of the DRAM 42 are read. When the second writing is completed, the image data of each image sensor 7 of each line Lx after the line L17 of the scanning line 5 is in the same order as the first or second writing order, and column columns 9 to 12 and columns column 13 to column 16 are used. Write to each small area.

  In this manner, the process of writing the image data from each image sensor 7 of each line Lx of the scanning line 5 to the row rowz of the DRAM 42 is repeated, and the image from each image sensor of the line L1024 that is the last line of the scanning line 5 is obtained. When the data is written in the small areas of the rows row 1793 to row 2048 and columns column 509 to column 512 of the DRAM 42, the memory controller 43 performs all imaging connected to all the lines L1 to L1024 of the scanning line 5 of the detection unit P of the radiographic imaging apparatus 1. The process of writing all image data from the element 7 to the DRAM 42 is completed.

  When the memory controller 43 performs the write control as described above, when each row rowz of the DRAM 42 is viewed, writing to each rowrowz of the DRAM 42 is performed every 8 lines in the reading process from each line of the scanning line 5. Will come to be. Accordingly, assuming that Td is the data write time for a plurality of rows (256 rows in the above example) of the image data for one line of the scanning lines 5 (1024 data in the above example) in the DRAM 42, each DRAM 42 In the case of the row rowz, the write operation is performed for each rowx at intervals of 8 × Td.

  That is, in the present embodiment, as described above, the writing process of the image data for each line Lx of the scanning line 5 to all the rows 1 to 2048 of the DRAM 42 is repeated, and the writing of the image data to the DRAM 42 is performed. However, since the time required to write image data to all the rows 1 to 2048 of the DRAM 42 at one time is 8 × Td as described above, a time interval of 8 × Td is set for each row rowz of the DRAM 42. Access is performed every time.

  Therefore, if the time interval ΔT (ie, 8 × Td in the above case) of the write operation to each row z of the DRAM 42 is adjusted in advance so as to be within the data holding time of each row z in the DRAM 42, the memory The controller 43 performs the write control as described above, so that it is not necessary to perform a refresh operation at least during the writing period of the image data from each image sensor 7 of the detection unit P to the DRAM 42, so-called refresh-free is realized. It becomes possible.

  The data writing time Td of the image data for one line of the scanning line 5 to the plurality of rows such as 256 in the DRAM 42 is the number of image data for one line of the scanning line 5, that is, the image as one line of the scanning line 5. Although it fluctuates according to the number of image sensors 7 from which data is read, it varies depending on other factors.

  For example, when writing image data to each row rowz of the DRAM 42, the memory controller 43 designates, for example, a row address and a first column address to which the image data is written, and image data for one row (4 in the above example). Image data) may be burst transferred.

  In that case, the number of image data written for one row, that is, the number of image data written to one row is set to one, the number is set to two, the number is set to four, eight,. Even if the time for writing image data to one row changes and the number of image data for one line of the scanning line 5 (1024 in the above example) is the same, the data writing times Td, That is, data writing to the row rowz ′ of the DRAM 42 of the last image data for one line of the scanning line 5 is started after data writing of the first image data for the scanning line 5 to the row rowz of the DRAM 42 is started. The time Td until ending is changed. In this case, when the number of image data written for one row changes, the number of rows of the DRAM 42 written so that the image data for one line of the scanning line 5 extends also changes.

  Further, when the number of image data to be written in one row of the DRAM 42 is changed in this way, the time interval ΔT of the writing operation for each row z of the DRAM 42 also changes. That is, as in the above example, when the number of image data for one line of the scanning line 5 is 1024 and the DRAM 42 is composed of rows 1 to 2048, the number of image data written for one row is one. If there is, the time interval ΔT of the write operation for each row z of the DRAM 42 is 2 × Td, so that 2 × 4 × Td, 4 × 8 × Td (that is, in the above example), 8 × Then, 16 × Td,...

  As described above, the data writing time Td of the image data for one line of the scanning line 5 to the plurality of rows of the DRAM 42 is equal to the configuration of the detection unit P in the radiation imaging apparatus 1 and the number of image data to be written to one row of the DRAM 42. As a result, the time interval ΔT of the write operation to each row rowz of the DRAM 42 varies.

  For this reason, in the present embodiment, the number of rows of the DRAM 42 written so that the image data for one line of the scanning line 5 straddles, the number of image data written for each row z, or the radiation image capturing apparatus 1 By appropriately setting each element such as the configuration, the time interval ΔT of the write operation to each row and rowz of the DRAM 42 is adjusted so as to be within the data holding time of each row and rowz in the DRAM 42.

  In the present embodiment, as described above, the image data for each line L1 to Lx of the scanning line 5 is written in the small areas of the row 1 to row 256 and the columns column1 to column4 of the DRAM 42 as the image data of the line L1, Each image data of the line L2 is written to the row 257 to row 512 of the DRAM 42 and the small areas of the columns column 1 to column 4, and each image data of the line L8 is written to the row 1793 to row 2048 of the DRAM 42 and the small areas of the columns column 1 to column 4. When the first writing to all the rows of the DRAM 42 is completed, the image data of other lines has already been written in the same order as the first writing order for the remaining image data of the scanning lines 5. Control is performed so as to write to a column different from the column of the DRAM 42, and the lines L 1 to L 1 of the scanning line 5 are So that the repeated writing process to all of the row of the DRAM42 image data for each x.

  In such a case, the writing process of the image data for each line L1 to Lx of the scanning line 5 to each row z of the DRAM 42 is repeated within the data holding time of the DRAM 42, respectively. The number of rows to be written and the number of data stored for each row rowz are set so that image data for one line is straddled.

  In the above example, the case where the image data from each image sensor 7 connected to each line Lx is read while the line number x is incremented sequentially from the line L1 of the scanning line 5 has been described. In some cases, image data from each image sensor 7 connected to each line Lx is read while the line number is decremented in order from the line (line L1024 in the above example).

  In such a case, it is possible to write the image data sequentially transmitted from the last line of the scanning line 5 in order from the small regions of the row 42 to row 256 and the columns column 1 to column 4 of the DRAM 42. In addition, it is also possible to configure so that writing is performed in the reverse order from the above-mentioned writing order in order from the small areas of the rows row 1793 to row 2048 and columns column 509 to column 512 of the DRAM 42.

  Further, in the above example, the image data of the imaging elements 7 of the lines L1 to L8 of the scanning line 5 is sequentially written for each small region of the columns column1 to column4 of all the rows row1 to row2048 of the DRAM 42, and the lines L9 to L16 are written. In this example, the image data of each line Lx of the scanning line 5 is sequentially written in the row direction and the column direction of the DRAM 42 so that the image data is sequentially written in the small areas of the columns column 5 to column 8 of the DRAM 42. However, it is not always necessary to configure such that the data is sequentially and sequentially written.

  However, by controlling writing so as to write in an orderly manner, it is easy to construct a control program and the like, and the number of image pickup elements 7 from which image data is read as one line of scanning lines 5 (ie, the so-called number of pixels). Even if each of the above-mentioned elements are variously different, it becomes possible to perform write control using the same control program only by changing the variable corresponding to each element without changing the basic configuration of the control program, The control program can be shared.

  In particular, when the image pickup apparatus is a digital camera, the number of pixels (number of pixels), the memory capacity of the installed DRAM, and the like are various, so it can be said that the merit of sharing the control program is very large.

  Further, when the image data is written in the DRAM 42 in an orderly manner as described above, there is an advantage that it is very easy to construct a read control when reading the image data. For example, when the image data is written to the DRAM 42 as in the above-described embodiment, the read order of the DRAM 42 is the same as the order of writing to the row rows of the DRAM 42 when the image data is written. The image data of each imaging device 7 of the lines L1 to L8 of the scanning line 5 is sequentially read for each small region of the columns column1 to column4, and the lines L9 to L16 of the scanning line 5 are read for each small region of the columns column5 to column8 of the DRAM 42. The readout control is performed so as to sequentially read out the image data of each of the imaging elements 7.

  As described above, since the reading operation may be performed in the same order as the writing order, the image data of each imaging element 7 can be easily and orderly read from the DRAM 42. In this case, the control program for the image data read control can be easily constructed by effectively utilizing the configuration of the write control program.

  As described above, the image data read from each image sensor 7 of each line Lx while decrementing the line number in order from the last line of the scanning line 5 (line L1024 in the above example) is used as the row row1 of the DRAM 42. When writing is performed in order from a small area of .about.row 256 and columns column 1 to column 4, it is possible to control to read out the image data from the DRAM 42 in the reverse order of the writing order.

  That is, in this case, in the read control, first, the image data of the line L1 of the scanning line is read from the small areas of the rows row 1793 to row 2048 and the columns column 509 to column 512 of the DRAM 42. Control is performed so that the image data of the line L2 of the scanning line is read from the small area of the column 512, and the image data of the last line of the scanning line is finally read from the small areas of the rows row1 to row256 of the DRAM 42 and the columns column1 to column4. To do.

  If configured to control in this manner, the image data for each line Lx is read from the DRAM 42 in order from the line L1 of the scanning line, so that the image is picked up by the image pickup apparatus such as the radiation image pickup apparatus 1 and read out from the image pickup apparatus. Processing such as inverting the top and bottom of the image becomes unnecessary.

  Therefore, the radiographic image taken by the radiographic imaging device 1 is displayed on the monitor screen of an external computer, the image taken by the digital camera is displayed on the liquid crystal display on the back, or the radiographic imaging device 1 takes a picture. When a radiographic image or an image taken by a digital camera is recorded on an image recording medium such as a film, the user can perform processing without worrying about upside down of the image.

  In addition, as described above, by controlling to read the image data in the same order as the order of writing the image data to the DRAM 42 or in the reverse order, the time interval of the reading operation of the image data from each row rowz of the DRAM 42 is changed. The time interval is equal to or similar to the time interval ΔT of the write operation to each rowz. Therefore, even in the operation of reading image data from each row rowz of the DRAM 42, it becomes possible to repeat the reading of image data from each row rowz within the data holding time of the DRAM 42, so there is no need to perform a refresh operation. It becomes possible to realize free.

  As described above, according to the imaging apparatus according to the present embodiment, when image data from each imaging device 7 of each line Lx of the scanning line 5 is written to the DRAM 42, the image data straddles a plurality of rows of the DRAM 42, and The data is written so that the number of data written for each row is equal to a part of the number of columns per row. At the same time, control is performed so that the image data for one line of the scanning line 5 is not written into the same plurality of rows as the image data of at least other adjacent lines, and the write operation to each row rowz of the DRAM 42 is performed. The time interval ΔT is controlled to be within the data holding time of the DRAM 42.

  For this reason, it is not necessary to perform the refresh operation during the writing period of the image data from each image sensor 7 of the detection unit P to the DRAM 42, so that it is possible to reduce the power consumed accordingly.

  Further, as described above, if the read control is performed so that the image data is read in the same order as or in the reverse order to the image data in the DRAM 42, the image data can be read from each row z in the DRAM 42. Thus, it becomes possible to repeat the reading of the image data from each row rowz within the data holding time of the DRAM 42, so that it is not necessary to perform a refresh operation, and so-called refresh-free can be realized. Therefore, with this configuration, it is not necessary to perform a refresh operation even during a period in which image data is read from the DRAM 42, and the power consumed correspondingly can be reduced.

  As described above, in addition to the case where the imaging device is a digital camera, in particular, the portable radiographic imaging device may be configured to avoid as much useless power consumption as possible in order to prevent the built-in battery from being consumed. Although requested, according to the radiographic image capturing apparatus 1 according to the present embodiment, it is possible to realize refresh-free in the operation of writing image data into the DRAM 42 and the operation of reading out image data from the DRAM 42 as described above. Therefore, it is possible to reduce the amount of power consumed, and to effectively prevent the built-in battery from being consumed.

  Needless to say, the present invention is not limited to the above-described embodiment, and can be changed as appropriate.

1 Radiographic imaging device (portable radiographic imaging device, imaging device)
5 Scanning line 6 Signal line 7, (x, y) Image sensor 8 TFT (switch element)
15 Scanning drive circuit 17 Reading circuit 40 Battery 42 DRAM
43 Memory controller
columnw Column Lx Scan line line P Detection area r
rowz Row ΔT Write operation time interval (time required for one write process)

Claims (7)

A plurality of image sensors that are provided in each region partitioned by a plurality of scanning lines and a plurality of signal lines arranged so as to cross each other and generate electric charges according to the amount of irradiated light are two-dimensional Detectors arranged in a shape,
A scanning drive circuit for sequentially switching the lines of the scanning lines to which a signal readout voltage is applied;
A switching element connected to each of the scanning lines and for discharging the charge accumulated in the imaging element to the signal line when the voltage for signal readout is applied;
A readout circuit that reads out the electric charge from the imaging device via the signal line and sequentially outputs image data for each imaging device;
DRAM in which image data for each image sensor is stored in a predetermined memory area;
A memory controller for controlling writing of the image data to the DRAM and reading of the image data from the DRAM;
With
The memory controller spans the image data for each line of the scanning line across a plurality of rows in the predetermined memory area of the DRAM, and the number of data written for each row is the number of columns per row. The image data for one line of the scanning line is at least the same as the image data of the other lines adjacent to the line in the detection unit. The imaging apparatus is controlled so as not to write data to the DRAM, and the time interval of the write operation to each row of the predetermined memory area of the DRAM is controlled to be within the data holding time of the DRAM.   The memory controller writes the image data for each line of the scanning line so that the image data is not written to the plurality of rows that are the same as the image data of other lines, and the predetermined data of the DRAM is written. When the first writing to all the rows in the memory area is completed, the image data for each of the remaining lines of the scanning line is already in the same order as the first writing order, and already in the other lines. Control is performed to write to a column different from the column of the DRAM in which the image data is written, and the writing process of the image data for each line of the scanning line to all the rows of the DRAM is repeated. The imaging apparatus according to claim 1.   In the memory controller, in the writing process of the image data for each line of the scanning line to all the rows of the DRAM, the image data for each line of the scanning line is written to each row of the DRAM. The number of rows written and the number of data stored for each row so that the image data for one line of the scanning line straddles so that the processing is repeated within the data holding time of the DRAM. The imaging apparatus according to claim 2, wherein is set.   When reading the image data from the DRAM, the memory controller controls the image data for each line of the scanning line to be read in the same order as the writing order to each row of the DRAM. The imaging apparatus according to any one of claims 1 to 3, wherein the imaging apparatus is characterized in that   When reading the image data from the DRAM, the memory controller reads the image data for each line of the scanning line in an order opposite to the order of writing to each row of the DRAM. The imaging apparatus according to claim 1, wherein the imaging apparatus is controlled.   6. The battery for supplying power to at least the detection unit, the scan driving circuit, the readout circuit, the DRAM, and the memory controller is built-in. 6. Imaging device. The imaging apparatus according to claim 6,
The imaging element of the detection unit is a radiation detection element that detects irradiated radiation, or a photoelectric conversion element that detects light in which the irradiated radiation is converted to another wavelength. Image shooting device.

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