JP2013192275A - Charger for radiation image photographing device, and radiation image detection system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable rapid charging by suppressing an influence of path resistance.SOLUTION: A charger 4 which charges a power storage body 28 embedded in a housing 21 of a radiation image photographing device 2 from the outside via connectors 26 and 42 comprises: a power source 41 for supplying power for charging; a voltage detector 43 for detecting the voltage of the power storage body; a current detector 44 for detecting a charging current; and a charge controller 45 for performing constant-current charging until a target voltage V1 is obtained, then switching over to constant-voltage charging. The charge controller detects voltage change ΔV of the power storage body by the voltage detector when current values are changed between at least two values at the start of the constant-current charging, and controls the charging by correcting the target voltage or the voltage value detected by the voltage detector in accordance with the change amount of the voltage of the power storage body.

Description

  The present invention relates to a charging device for a radiographic imaging device and a radiographic image detection system.

In recent years, radiographic imaging devices called flat panel detectors (FPDs), which are means for acquiring medical radiographic images, have built-in power storage units consisting of capacitors and secondary batteries, and are cable-less. A cassette-type radiation image capturing apparatus configured to be portable is developed (see, for example, Patent Document 1).
When the radiographic imaging apparatus is configured to be portable, it is possible to perform imaging with a high degree of freedom including portable imaging on a patient's bedside or the like.

  By the way, from the viewpoint of preventing overcharging, the charging of the power storage unit is preferably performed by constant voltage charging that can be easily performed up to a target voltage (for example, the rated voltage of the power storage unit). Constant voltage charging has a problem that it takes too much time to charge. Therefore, in recent years, constant current charging is performed until the detection voltage of the battery reaches the target voltage, and switching to constant voltage charging is reached when the target voltage is reached. The method is employed (for example, see FIG. 6 of Patent Document 2).

JP 2009-237074 A JP-A-11-250939

By the way, in the said charging method, it is necessary to detect and monitor the voltage of an electrical storage body more correctly. In this case, if voltage detection means can be provided in the immediate vicinity of the power storage unit, [detection voltage≈actual battery voltage], and the voltage detection of the power storage unit can be performed more accurately.
However, the cassette-type radiographic imaging device is required to be thin and small, and it is difficult to secure the installation space for the charging circuit including the voltage detection means inside the cassette when trying to realize this. Become.
For this reason, it is conceivable that a charging circuit including voltage detection means is provided on the external charging device side for setting the cassette type radiographic imaging device at the time of charging, and the voltage of the power storage unit is detected from the outside of the radiographic imaging device.
However, when the voltage detection means is provided outside the cassette, the distance from the power storage body to the voltage detection means becomes long, so that there is an influence of path resistance in the wiring or the like between them, and [detection voltage = actual power storage Body voltage + charging current x path resistance], so a voltage higher than the actual voltage of the battery is detected, so switch from constant current charging to constant voltage charging before the battery actually reaches the target voltage Since the power storage unit starts constant voltage charging at a voltage lower than planned, constant voltage charging is performed for a long time, which may increase the time required for charging.

  An object of the present invention is to increase the speed of charging while making it possible to reduce the size of a radiographic imaging apparatus.

In order to solve the above-described problem, a charging device for a radiographic imaging device according to the present invention includes:
A charging device that charges the power storage unit from the outside of the housing through a connector provided between the radiographic imaging device having a power storage unit that supplies power to each functional unit inside the housing. And
A power supply unit for supplying power for charging the power storage unit;
A voltage detection unit for detecting a voltage of the power storage unit;
A current detection unit for detecting a charging current flowing through the power storage body during the charging;
A constant current charging is performed until the voltage of the power storage unit detected by the voltage detection unit reaches a target voltage, and a charge control unit that switches to constant voltage charging when the voltage of the power storage unit reaches the target voltage,
The charge controller is
Changing the charging current between at least two values at the start of the constant current charging and detecting the voltage change of the power storage unit accompanying the current change by the voltage detection unit;
Charging control is performed by correcting the value of the target voltage or the detection voltage of the voltage detection unit in accordance with the amount of change in the voltage of the power storage unit.

Moreover, the radiographic image detection system which is another aspect of this invention is the following.
A radiographic imaging device that houses a power storage unit that supplies power to each functional unit inside the housing, and the radiographic imaging device from the outside of the housing to the power storage unit through a connector provided between the radiographic imaging device. A radiological image detection system comprising a charging device for charging,
The charging device is:
A power supply unit for supplying power for charging the power storage unit;
A voltage detection unit for detecting a voltage of the power storage unit;
A current detection unit for detecting a charging current flowing through the power storage body during the charging;
A constant current charging is performed until the voltage of the power storage unit detected by the voltage detection unit reaches a target voltage, and a charge control unit that switches to constant voltage charging when the voltage of the power storage unit reaches the target voltage,
The charge controller is
Changing the charging current between at least two values at the start of the constant current charging and detecting the voltage change of the power storage unit accompanying the current change by the voltage detection unit;
Charging control is performed by correcting the value of the target voltage or the detection voltage of the voltage detection unit in accordance with the amount of change in the voltage of the power storage unit.

In the present invention, the charge control unit changes the current value between at least two values at the start of constant current charging.
These two values may be, for example, current values immediately before and immediately after the start of constant current charging, or energization may be performed with arbitrary different current values at the start of constant current charging.
As described above, when the current value is changed in binary, the amount of change in the voltage value detected in each current value is the resistance value of the path from the power storage unit to the voltage detection unit due to the difference between the current values in the two values. It is almost equal to the value multiplied by.
Therefore, the error of the detected voltage due to the path resistance in constant current charging can be obtained from the relationship between the change in the current value in binary and the change in the voltage value at that time. Then, by correcting the voltage error with respect to the target voltage value or by correcting the voltage error with respect to the detection voltage value of the voltage detection unit, constant current charging is performed until the power storage unit becomes closer to the target voltage. Therefore, the transition from constant current charging to constant voltage charging at a voltage lower than planned can be avoided, and the time required for charging can be shortened.
Further, this makes it possible to provide the charging device side without providing the voltage detection unit on the radiographic imaging device side, so that the radiographic imaging device can be reduced in size and thickness.
Furthermore, by not providing a voltage detection unit on the radiographic imaging device side, there is no need for a connector, a terminal, or the like for transmitting a detection voltage signal from the radiographic imaging device to the charging device side, and further miniaturization of the radiographic imaging device. It is possible to reduce the thickness.

It is the schematic which shows the system configuration | structure of the radiographic image detection system which concerns on 1st Embodiment. It is a perspective view which shows the external appearance of the radiographic imaging apparatus shown in FIG. It is an equivalent circuit diagram which shows the structure of the sensor panel part, reading part, etc. of the radiographic imaging apparatus shown in FIG. It is the block diagram which illustrated only the structure relevant to charge of the cradle and radiographic imaging apparatus shown in FIG. FIG. 5A is a diagram showing temporal changes in the detected voltage (solid line) and the actual battery voltage (broken line) in the charge control, and FIG. 5B is a line showing temporal changes in the charge current in the charge control. FIG. FIG. 6A is a diagram showing temporal changes in the detection voltage (solid line) and the actual voltage of the battery (broken line) in the charging control by the charging control unit, and FIG. 6B is the charging in the charging control by the charging control unit. It is a diagram which shows the time change of an electric current. It is a block diagram which shows the system configuration | structure of a radiographic imaging system. It is a flowchart which shows the flow of the charge control by a charge control part. FIG. 9A is a diagram showing temporal changes in the detected voltage (solid line) and the actual voltage of the battery (broken line) when the charging current is changed a plurality of times at the start of constant current charging, and FIG. FIG. 9C is an enlarged diagram of the temporal change of the detection voltage at the start of constant current charging. It is the block diagram which illustrated only the structure relevant to charge of the cradle and radiographic imaging apparatus in 2nd Embodiment. FIG. 11A shows a heavy electric control in the second embodiment, and FIG. 11A is a diagram showing a temporal change of a detection voltage (solid line) and an actual battery voltage (broken line) in the charging control by the charging control unit. (B) is a diagram which shows the time change of the charging current in the charge control by a charge control part. FIG. 12A shows heavy electric control in the third embodiment, and FIG. 12A is a diagram showing temporal changes in detected voltage (solid line) and actual battery voltage (broken line) in charge control by the charge control unit. (B) is a diagram which shows the time change of the charging current in the charge control by a charge control part.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. Note that embodiments to which the present invention is applicable are not limited to this.

[First Embodiment]
A first embodiment of the present invention will be described with reference to FIGS. However, embodiments to which the present invention can be applied are not limited to those shown in the drawings.

FIG. 1 is a diagram showing a schematic configuration of a radiographic image detection system 1, and FIG. 2 is a perspective view of a radiographic image capturing apparatus in the present embodiment.
As shown in FIG. 1, the radiological image detection system 1 according to the present embodiment includes a radiographic image capturing device 2 including a battery 28 as a power storage unit, and a cradle 4 on which the radiographic image capturing device 2 is placed. ing.

(Radiation imaging equipment)
In this embodiment, the radiographic image capturing apparatus 2 is a portable cassette type FPD in which a so-called flat panel detector (hereinafter referred to as “FPD”) is configured in a cassette type, and is used for radiographic image capturing. Image data (hereinafter simply referred to as “image data”) is acquired.
In the following, a so-called indirect radiation image capturing apparatus that includes a scintillator or the like and converts the emitted radiation into electromagnetic waves of other wavelengths such as visible light to obtain an electrical signal will be described as the radiation image capturing apparatus 2. However, the present invention can also be applied to a so-called direct type radiographic imaging apparatus that directly detects radiation with a radiation detection element without using a scintillator or the like.

As shown in FIG. 2, the radiographic image capturing apparatus 2 includes a housing 21 that protects the inside. The housing 21 has at least a surface X on which radiation is received (hereinafter referred to as a radiation incident surface X) formed of a material such as a carbon plate or plastic that transmits radiation.
FIG. 2 shows a case where the casing 21 is formed of a front member 21a and a back member 21b. However, the shape and configuration are not particularly limited. It is also possible to form a cylindrical so-called monocoque shape or the like.

  As shown in FIG. 2, in the present embodiment, a power switch 22, an indicator 25, an apparatus-side connector portion 26, and the like are disposed on the side surface portion of the radiographic image capturing apparatus 2.

  The power switch 22 is used to switch on / off the power of the radiographic image capturing apparatus 2. By operating the power switch 22, each functional unit of the radiographic image capturing apparatus 2 by a battery 28 (see FIG. 1) described later. A signal instructing the start and stop of the power supply is output to a main body control unit 30 (see FIG. 1) described later. When the radiographic imaging device 2 is not used for imaging, the power consumption of the battery 28 can be suppressed by turning off the power supply (that is, stopping the power supply to each functional unit by the battery 28).

  The indicator 25 is composed of, for example, an LED or the like, and displays the remaining amount of charge of the battery 28 and various operation statuses.

In addition, the radiographic imaging apparatus 2 is provided with a battery 28 that supplies power to each functional unit of the radiographic imaging apparatus 2.
The battery 28 is rechargeable, and uses, for example, a lithium ion secondary battery. In addition, a storage element such as a lithium ion capacitor (LIC) or an electric double layer capacitor can be applied.

  In addition, a lid member 70 that is opened and closed for replacement of the battery 28 built in the housing 21 is provided on the side surface portion of the radiographic image capturing apparatus 2. An antenna device 71 is embedded for the image capturing apparatus 2 to transmit and receive information to and from the outside via a wireless access point 113 (see FIG. 7) described later.

The device-side connector portion 26 (shown simply as “connector portion” in FIG. 1) is configured to be electrically connectable to the cradle 4 and is detachable from each other.
Further, the device-side connector portion 26 is provided at a position corresponding to the cradle output connector portion 42 when the radiographic imaging device 2 is placed on the cradle 4.

A power supply circuit 29 is provided between the battery 28 and each functional unit. The power supply circuit 29 is a functional unit that appropriately converts and adjusts the voltage value and the like so that the power supplied from the battery 28 is suitable for each functional unit that is the supply destination.
The functional units referred to here are modules or devices that execute various functions in radiographic imaging and require power supply in the radiographic imaging apparatus 2. A storage unit 31, a scanning drive circuit 32, a signal readout circuit 33, a signal processing unit 34, a communication unit 35, and an A / D conversion unit 40, which will be described later, correspond to this.

A scintillator layer (not shown) that absorbs radiation incident from the radiation incident surface X and converts it into light having a wavelength including visible light is formed inside the radiation incident surface X (see FIG. 2) of the housing 21. As the scintillator layer, for example, a layer formed by using a phosphor in which a luminescent center substance is activated in a mother body such as CsI: Tl, Gd ₂ O ₂ S: Tb, ZnS: Ag, or the like can be used.

  A plurality of photoelectric conversion elements 23 (see FIG. 3) that convert light output from the scintillator layer into electric signals are two-dimensionally provided on the surface of the scintillator layer opposite to the surface on which radiation is incident. A sensor panel unit 24 is provided as the arranged detection means. The photoelectric conversion element 23 is, for example, a photodiode, and constitutes a radiation detection element that converts the radiation transmitted through the subject into an electrical signal together with the scintillator layer and the like.

  In this embodiment, a reading unit 45 (see FIG. 3) is a reading unit that reads the output value of each photoelectric conversion element 23 of the sensor panel unit 24 by the main body control unit 30, the scanning drive circuit 32, the signal reading circuit 33, and the like. ) Is configured.

The configurations of the sensor panel unit 24 and the reading unit 45 will be further described with reference to the equivalent circuit diagram of FIG.
As shown in FIG. 3, one electrode of each photoelectric conversion element 23 of the sensor panel unit 24 is connected to a source electrode of a TFT 46 which is a signal reading switch element. In addition, a bias line Lb is connected to the other electrode of each photoelectric conversion element 23, and the bias line Lb is connected to a bias power supply 36, and a reverse bias voltage is applied from the bias power supply 36 to each photoelectric conversion element 23. It has come to be.

  The gate electrode of each TFT 46 is connected to a scanning line Ll extending from the scanning drive circuit 32, and a read voltage (ON voltage) or OFF voltage is applied to the gate electrode of the TFT 46 from a TFT power source (not shown) via the scanning line Ll. Is applied. The drain electrode of each TFT 46 is connected to the signal line Lr. Each signal line Lr is connected to an amplifier circuit 37 in the signal readout circuit 33, and an output line of each amplifier circuit 37 is connected to an analog multiplexer 39 via a sample hold circuit 38. The signal readout circuit 33 is connected to an A / D converter 40 as processing means for converting the signal into a digital signal. The analog image signal sent from the analog multiplexer 39 is an A / D converter. 40 is converted into a digital image signal. The signal readout circuit 33 is connected to the main body control unit 30 via the A / D conversion unit 40, and a digital image signal is output to the main body control unit 30. A storage unit 31 is connected to the main body control unit 30, and the main body control unit 30 stores the digital image signal sent from the A / D conversion unit 40 in the storage unit 31 as image data. Yes.

  The main body control unit 30 is a computer including a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and the like (not shown), and comprehensively controls the entire radiographic imaging apparatus 2.

The ROM stores a live-action image data generation process, an offset correction value generation process, a program for performing various processes in the radiation image capturing apparatus 2, various control programs, parameters, and the like.
The main body control unit 30 reads a predetermined program stored in the ROM, develops it in the work area of the RAM, and the CPU executes various processes according to the program.

  The signal processing unit 34 is a functional unit that converts the image data into data in a format suitable for output to the outside by performing predetermined signal processing on the image data.

The storage unit 31 is configured by, for example, an HDD (Hard Disk Drive), a flash memory, or the like. The storage unit 31 includes actual image data generated by the reading unit 45 (see FIG. 3) (radiation transmitted through the subject). Based image data), dark image data (image data acquired without radiation), and the like are stored.
The storage unit 31 may be a built-in memory or a removable memory such as a memory card. Further, the capacity is not particularly limited, but preferably has a capacity capable of storing a plurality of pieces of image data. By providing such a storage means, it is possible to continuously irradiate a subject with radiation, and to record and accumulate image data each time, enabling continuous shooting and moving image shooting. Become.

The communication unit 35 is connected to the antenna device 71, and transmits / receives various signals to / from an external device such as the console 101 under the control of the main body control unit 30. The communication unit 35 communicates with an external device such as the console 101 in a wireless manner via the wireless access point 113 (see FIG. 7).
In the present embodiment, the communication unit 35 transmits image data based on an image signal read by the reading unit 45 and converted from an analog signal to a digital signal by the A / D conversion unit 40 to the console 101 which is an external device and the console. The imaging order information and the like are received from 101 and the like.

(Cradle)
The cradle 4 is a charging device for a capacitor configured to be able to supply power to the radiographic image capturing apparatus 2 from the outside by placing the radiographic image capturing apparatus 2. FIG. 4 is a block diagram illustrating only the configuration related to the charging of the cradle 4 and the radiation image capturing apparatus 2.
As shown in FIG. 4, the cradle 4 includes a radiographic image taken from an AC / DC constant voltage power supply unit 41 to which an outlet 8 connected to an external power supply (not shown) is connected, and from the AC / DC constant voltage power supply 41 during charging. The output connector 42 as a connector for applying a charging voltage to the battery 28 of the apparatus 2 and the battery 28 of the radiation imaging apparatus 2 from the AC / DC constant voltage power supply 41 through the wirings L1 and L2 of the output connector 42. A voltage detection unit 43 that detects voltages at both ends (between both electrodes), a current detection unit 44 that detects a current flowing through the wiring L1 when the battery 28 of the radiographic imaging apparatus 2 is charged, and an AC / DC constant voltage power supply unit 41 And a charging control unit 45 that selectively controls constant current charging and constant voltage charging.

The output connector portion 42 is provided at a position that matches the device-side connector 26 of the radiographic imaging device 2 when the housing of the radiographic imaging device 2 is inserted into the slot 4a formed in the cradle 4. Two terminals 42a and 42b of a positive electrode and a negative electrode elastically supported so as to be press-contactable to the side connector 26 are provided.
The device-side connector 26 of the radiographic imaging device 2 is provided with terminals 26a and 26b connected to the positive electrode and the negative electrode of the battery 28. When the radiographic imaging device 2 is inserted into the slot 4a, the positive electrode A state is formed in which the terminals and the negative terminals are in press contact with each other and can be energized.

The AC / DC constant voltage power supply 41 includes an A / D converter that is connected to an outlet 8 that is an external AC power supply and outputs a constant DC voltage power supply, and a PWM output circuit including a switching element.
The switching element of the PWM output circuit is turned on and off by the charge control unit 45, and the duty ratio thereof is arbitrarily controlled, so that constant current charging and constant voltage charging for the battery 28 can be performed. It is possible.

The current detection unit 44 can output a detection signal corresponding to the charging current to the charge control unit 45 by a load provided on the wiring L1.
The voltage detection unit 43 detects the voltage between the wiring L1 and the wiring L2, thereby detecting the voltage of the battery 28 and outputting it to the charging control unit 45. The voltage detection unit 43 detects the voltage in the state affected by the voltage drop (detection voltage error) due to the wiring from the voltage detection unit 43 to the battery 28 and the resistances of the connectors 42 and 26. And output to the charge controller 45.

  The charging control by the charging control unit 45 will be described with reference to FIGS. FIG. 5 is a diagram showing changes in the voltage and charging current of the battery 28 when the conventional charging method is applied, and FIG. 6 shows changes in the voltage and charging current of the battery 28 in the charging control performed by the charging control unit 45. FIG.

FIG. 5A shows temporal changes in the detected voltage (solid line) and the actual battery voltage (broken line) in the charge control, and FIG. 5B shows temporal changes in the charge current in the charge control.
In the example of FIG. 5, at the time of charging the battery 28, first, constant current charging is performed so as to maintain a predetermined charging current Is (for example, 10 [A]). Reaches the target voltage V1 (for example, the rated voltage of the battery 28 or a value that is less than and close to the rated voltage, for example, 4.2 [V]), switching to constant voltage charging is performed to maintain the target voltage V1. Then, the charging is terminated when the charging current becomes equal to or less than a predetermined charging end value Ie.
However, in the case of this example, as in the case of the radiographic image detection system 1, when the voltage detection unit 43 in the cradle 4 outside the radiographic image capturing apparatus 2 performs voltage detection of the battery 28, Since the distance of the voltage detection unit 43 is far, the influence of the path resistance occurs, and the actual voltage of the battery 28 is switched to constant voltage charging before reaching the target voltage V1.
As a result, there arises a problem that the time required for constant voltage charging increases.

6A shows temporal changes in the detected voltage (solid line) and the actual battery voltage (broken line) in the charging control by the charging control unit 45, and FIG. 6B shows charging in the charging control by the charging control unit 45. It shows the change in current over time.
In the charging control unit 45, the target voltage for constant current charging is set to V1 as in the example of FIG. 5, but the target voltage is changed from V1 in consideration of the effect of voltage drop (detection voltage error) due to path resistance. It is characterized by correcting to V2.

That is, the charging control unit 45 maintains the charging current Is (for example, 10 [A]) having a predetermined value as the charging current detected by the current detection unit 44 when the battery 28 is charged. The AC / DC constant voltage power supply 41 is controlled to start constant current charging.
At this time, the charge control unit 45 detects and stores the voltage change ΔV1 between the two current values before and immediately after the start of energization at the start of the constant current charging by the voltage detection unit 43. The charging current rises from 0 to Is before and after the start of energization, and the detection voltage rises from 0 to ΔV1. If the period in which these changes occur is sufficiently short, the actual voltage of the battery 28 hardly increases, so the voltage change ΔV1 is considered to be caused by the path resistance between the voltage detector 43 and the battery 28.

That is, while constant current charging is performed while maintaining the charging current Is, a value obtained by adding the voltage change ΔV1 due to the path resistance to the actual voltage of the battery 28 is detected by the voltage detection unit 43.
Therefore, when the constant current charging is performed until the battery 28 reaches the target voltage V1, the charging control unit 45 performs correction by adding ΔV1 to the target voltage V1, and calculates a new target voltage V2 ( V2 = V1 + ΔV1). Then, the constant current control is continuously executed until a new target voltage V2 in which the voltage detected by the voltage detector 43 is corrected is reached. Thus, constant current control can be performed until the actual voltage of the battery 28 reaches the initial target voltage V1.

  When the detected voltage of the battery 28 reaches the target voltage V2, the target voltage is returned to V1 and constant voltage charging is executed. Then, the charging is terminated when the gradually decreasing charging current becomes equal to or less than a predetermined charging end value Ie. In constant voltage charging, the charging current decreases, so the influence of the path resistance gradually decreases. Finally, there is almost no difference between the detected voltage and the actual voltage of the battery 28. There is no need to correct the target voltage.

(Radiation imaging system)
In addition, this radiographic image detection system 1 is arrange | positioned and used in the radiographic imaging system 100 as shown, for example in FIG.
The radiographic image capturing system 100 includes, for example, the radiographic image detection system 1 and a console 101 that can communicate with the radiographic image capturing apparatus 2 constituting the radiographic image detection system 1.

As shown in FIG. 7, the radiographic imaging device 2 is provided in an imaging room R1 that performs imaging of a subject (an imaging target site of the patient M) that is a part of the patient M by irradiating radiation, for example. The console 101 is provided corresponding to the photographing room R1.
In the present embodiment, a case where one radiographing room R1 is provided in the radiographic imaging system and three radiographic imaging apparatuses 2 are arranged in the radiographic room R1 will be described as an example. The number of imaging rooms and the number of radiation image capturing apparatuses 2 provided in each imaging room are not limited to the illustrated example.
Further, when there are a plurality of shooting rooms R1, the console 101 may not be provided corresponding to each shooting room R1, and one console 101 may be associated with the plurality of shooting rooms R1. Good.

In the radiographing room R1, a bucky device 110 having a cassette holding unit 111 capable of loading and holding the radiographic imaging device 2, and a radiation source such as an X-ray tube that irradiates the subject (the imaging target site of the patient M) A radiation generator 112 is provided which comprises (not shown). The cassette holding unit 111 is for loading the radiographic image capturing apparatus 2 at the time of photographing.
FIG. 7 illustrates the case where a bucky device 110a for standing position photography and a bucky device 110b for standing position photography are respectively provided in the photography room R1. The number of the bucky devices 110 provided in is not particularly limited. Further, in the present embodiment, a configuration in which one radiation generation device 112 is provided corresponding to each Bucky device 110 is illustrated, but for example, one radiation generation device 112 is provided in the imaging room R1. One radiation generation device 112 may correspond to a plurality of the bucky devices 110, and may be used by appropriately moving the position or changing the radiation irradiation direction.

  In addition, since the radiographing room R1 is a room that shields radiation and radio waves for radio communication are blocked, the radiographic imaging apparatus 2 communicates with an external device such as the console 101 in the radiographing room R1. Are provided with a wireless access point (base station) 113 for relaying these communications.

  In the present embodiment, a front room R2 is provided adjacent to the photographing room R1. In the anterior chamber R2, a radiographer, a doctor, etc. (hereinafter referred to as an “operator”) control the tube voltage, tube current, irradiation field stop, etc. of the radiation generator 112 that irradiates the subject with radiation. An operation device 114 for operating the device 110 is disposed.

  A control signal for controlling the radiation irradiation condition of the radiation generating device 112 is transmitted from the console 101 to the operation device 114, and the radiation irradiation condition of the radiation generating device 112 is transmitted to the console 101. It is set according to the control signal from. Examples of radiation irradiation conditions include exposure start / end timing, radiation tube current value, radiation tube voltage value, filter type, and the like.

  An exposure instruction signal for instructing radiation exposure is transmitted from the operation device 114 to the radiation generation apparatus 112. The radiation generation apparatus 112 applies predetermined radiation according to the exposure instruction signal for a predetermined time, Irradiation is performed at a predetermined timing.

The console 101 is a computer including a control unit configured by a CPU (Central Processing Unit), a storage unit, an input unit, a display unit, a communication unit (all not shown), and the like.
The console 101 displays an image based on the image data sent from the radiation image capturing apparatus 2 on the display unit, and performs various image processing on the image data.
In the present embodiment, the console 101 is connected to external devices such as the HIS / RIS 121, the PACS server 122, and the imager 123 via the network N.

In the radiographic imaging system 100, the radiographic image capturing apparatus 2 is in a disconnected state with respect to the cradle 4 or the power supply cable 5, and a radiographic image is captured and is in a connected state with respect to the cradle 4 or the power supply cable 5. The radiographic image capturing and charging are performed individually or in parallel.
The cradle 4 and the power supply cable 5 constitute a part of the radiographic image capturing system 100, but the illustration thereof is omitted in FIG.

(Charge control of radiation image detection system)
Here, the charging control performed by the radiation image capturing apparatus 2 will be described with reference to FIG. FIG. 8 is a flowchart showing a flow of charge control by the charge control unit 45.
When the radiographic imaging device 2 is connected to the cradle 4, the charging control unit 45 starts constant current charging. At this time, the target voltage for terminating the constant current charging is set to V1 (step S1).
Further, the charging control unit 45 detects the voltage change ΔV1 when the charging current is raised from 0 to Is at the start of constant current charging by the voltage detection unit 43 (step S3).

Next, the charging control unit 45 performs correction by adding ΔV1 to the target voltage V1, and sets a new target voltage V2 (step S5).
Thereafter, while maintaining the charging current at Is and continuing the constant current charging, the determination whether the voltage detected by the voltage detection unit 43 has reached the target voltage V2 is repeated (step S7).

When the detected voltage reaches the target voltage V2, the charge control unit 45 returns the target voltage to V1 and performs charging by switching from constant current charging to constant voltage charging (step S9).
Thereafter, while maintaining the detection voltage at V1 and continuing the constant voltage charging, the determination as to whether the charging current by the current detection unit 44 has dropped to the charging end value Ie is repeated (step S11).
And if it detects that the charging current by the electric current detection part 44 fell to the charge end value Ie, charge control will be complete | finished.

(Technical effects of radiation image detection system)
The charge control unit 45 of the cradle 4 of the radiological image detection system 1 uses the voltage detection unit 43 to detect the voltage change ΔV1 of the battery 28 accompanying the current change when the charging current is raised from 0 to Is at the start of constant current charging. The constant current charging is performed with the new target voltage V2 corrected by adding the voltage change ΔV1 to the initial target voltage V1 value, so that the path resistance between the voltage detector 43 and the battery 28 The influence due to the detection error can be reduced, and the voltage actually applied to the battery 28 during constant current charging can be made closer to the initial target voltage V1.
For this reason, when shifting from constant current charging to constant voltage charging, the battery 28 can be pulled up to a state as close as possible to the target voltage V1, and redundancy of constant voltage charging can be avoided and charging can be completed quickly. It becomes possible.

In addition, as described above, even if the path resistance of the voltage detection unit 43 from the battery 28 increases, the influence can be suppressed, so that the voltage detection unit 43 can be provided outside the radiographic imaging device 2, The radiation image capturing apparatus 2 can be reduced in size and thickness.
Further, since it is not necessary to provide a voltage detection unit on the side of the radiographic imaging device 2, there is no need for a connector, a terminal, or the like for transmitting the detection voltage signal from the radiographic imaging device 2 to the charging device side. Can be achieved.

(Other)
The charging control unit 45 performs correction by adding the voltage change amount ΔV1 to the target voltage V1 for constant voltage charging, but constant current charging without correcting the target voltage V1 for constant voltage charging. It is also possible to perform correction to always subtract the voltage detected by the voltage detector 43 by the voltage change amount ΔV1 and perform charge control to shift to constant voltage charging when the target voltage V1 is reached. The same applies to other embodiments described hereinafter.

In the charge control, only a change between two values of the charge current at the start of constant current charge (change in which the charge current rises from 0 to Is) is executed once, but FIG. 9B As shown, the change between the two values of the charging current may be repeated a plurality of times. In this example, the charging current is raised, lowered, and raised three times in total.
Then, as shown in FIGS. 9A and 9C, all detected voltage variations ΔV11, ΔV12, ΔV13 corresponding to the respective changes in the state of the charging current are detected, and the average values thereof are obtained, and the average The target voltage V1 may be corrected using the value.
Note that the current value may be changed between two different values each time, not only when the charging current is changed a plurality of times between the same two values. In this case, the amount of change in the detection voltage is not averaged, but the path resistance obtained by the change in the current value and the change in the detection voltage, which will be described later, is averaged.

In the charging control, the charging current is changed by two values of 0 and current Is at the start of constant current charging, the change amount ΔV of the detected voltage at that time is obtained, and the target voltage V1 is corrected. The two values of the charging current to be changed in order to obtain the change amount ΔV of the detection voltage are not limited to 0 and Is, and any two values can be selected.
However, when the change amount ΔV of the detected voltage when the charging current is changed by an arbitrary binary value is detected, ΔV is not added as it is to the target voltage V1 and corrected, but the arbitrary two of the charging current is corrected. The path resistance is calculated from ΔV / ΔI from the change amount ΔI in value and the detected voltage change amount ΔV, and the value obtained by multiplying the path resistance ΔV / ΔI by the charging current Is during constant current charging is added to the target voltage. Value.

In the charge control, the charge control unit 45 calculates a new target voltage V2 by adding the voltage change amount ΔV1 detected when the charge current is raised from 0 to Is as a correction value to the target voltage V1 as it is. However, for example, a value obtained by multiplying the correction value ΔV1 by a coefficient (less than 1, for example, 0.9) may be added to the target voltage V1.
As a result, the target voltage is corrected to be low, but overcharging of the battery 28 due to an unexpected factor can be more strictly avoided.

[Second Embodiment]
A second embodiment of the present invention will be described with reference to FIGS.
In the second embodiment, the radiation image capturing apparatus 2 includes the backflow prevention circuit 27 and the charge control unit 45 performs charge control corresponding to the backflow prevention circuit 27.

FIG. 10 is a block diagram illustrating only a configuration related to charging of the cradle 4 and the radiographic imaging device 2.
As shown in the figure, a backflow prevention circuit 27 is provided between the apparatus-side connector 26 and the battery 28 of the radiographic image capturing apparatus 2 so that no current flows from the battery 28 to the outside through the apparatus-side connector 26. The backflow prevention circuit 27 includes a switching element (not shown) between the device-side connector 26 and the battery 28, and unless an open voltage Vo greater than a predetermined value from the outside to the battery 28 is applied to the device-side connector 26, It has a function of electrically disconnecting between the apparatus-side connector 26 and the battery 28, thereby preventing discharge from the apparatus-side connector 26 when the radiographic image capturing apparatus 2 is not installed in the cradle 4. doing.

  Since the charging control unit 4 cannot detect the voltage of the battery 28 unless the backflow prevention circuit 27 is connected, the charging voltage of the open voltage Vo when the radiographic imaging device 2 is inserted into the slot 4a of the cradle 4. Application is started, and the voltage of the battery 28 can be detected. Note that the open-circuit voltage Vo is set to a value sufficiently smaller than the voltage applied to the backflow prevention circuit 27 by energizing the charging current Is of constant current charging. For example, while the charging current Is is 10 [A], the open circuit voltage Vo is a value equal to the voltage applied to the backflow prevention circuit 27 by energizing 1 [A].

Then, when starting constant current charging, the charging control unit 4 first energizes at the bare current value Io to which the open circuit voltage Vo can be applied, and controls the AC / DC constant voltage power supply 41 from this state. To the charging current value Is. Then, the charging control unit 4 detects and stores the change amount ΔV2 of the detected voltage due to the change in the two states of the charging currents Io and Is.
If the current change amount from the charging current Io to Is is ΔI2, the path resistance Rk2 satisfies Rk2 = ΔV2 / ΔI2.
The charge controller 45 calculates the path resistance Rk2 and sets a value obtained by multiplying the charge current Is as a correction value for the target voltage V1. That is, the corrected target voltage V2 is calculated by V2 = V1 + Rk2 · Is and constant current charging is performed until the target voltage V2 is reached. Thereafter, the target voltage is returned to V1 and constant voltage charging is performed. , The charging control is terminated when the charging value reaches the charging end value Ie. The charging end value Ie is set to a value larger than the current value Io at the open circuit voltage Vo.

  As described above, even when the radiographic imaging device 2 includes the backflow prevention circuit 27, the radiographic image detection system 1 can suppress the influence of the path resistance and can shorten the charging time. The radiation image capturing apparatus 2 can be reduced in size and thickness.

[Third Embodiment]
A third embodiment of the present invention will be described with reference to FIG.
In the first embodiment, the charging control unit 45 calculates the new target voltage V2 by adding and correcting the voltage change amount ΔV1 detected when the charging current is raised from 0 to Is, to the target voltage V1. For example, when switching from constant current charging to constant voltage charging due to a case where an error is included in the charging current or the detection voltage, the detection voltage is lower than expected with respect to the target voltage V1, As a result, constant voltage charging may take a long time.
In such a case, two charging current values Is1, is2 (Is1> is2) may be set, and constant voltage charging may be performed after performing constant current charging in two stages.

That is, the charging control unit 45 performs the first constant current charging with the charging current Is1 as in the first embodiment, and when the detected voltage reaches the corrected target voltage V2, the charging current is reduced to Is2. The second constant current charging is performed.
At this time, the charge control unit 45 uses the voltage detection unit 43 to detect the change amount ΔV3 of the detection voltage when the charging current changes from Is1 to Is2. Then, the value of the path resistance Rk3 is calculated from Rk3 = ΔV3 / ΔI3 (where ΔI3 = Is1-Is2).
The charging control unit 45 multiplies the path resistance Rk3 by the charging current Is2, and calculates an error in the detection voltage. Then, the target voltage V3 in the second constant current charge is calculated by V3 = V1 + Rk3 · Is2, and the second constant current charge is executed until the detected voltage reaches the target voltage V3.
Thereafter, constant voltage charging is performed in the same manner as in the first embodiment, and charging control is terminated.

  In this way, by reducing the charging current stepwise and performing constant current charging in two steps, the detection voltage error due to the path resistance can be reduced, and the target voltage is corrected and constant current charging is performed. In addition to the effect of reducing the detection voltage error due to the path resistance in some cases, the battery can be charged to a voltage closer to the target voltage before performing constant voltage charging, making it possible to further speed up charging. Become.

DESCRIPTION OF SYMBOLS 1 Radiation image detection system 2 Radiation image imaging device 4 Cradle (charging device)
21 Housing 26 Device side connector (connector)
28 Battery (power storage unit)
29 Power supply circuit 30 Main body control unit (function unit)
31 Storage unit (function unit)
32 Scanning drive circuit (functional part)
33 Signal readout circuit (functional part)
34 Signal processing part (functional part)
35 Communication Department (Function Department)
40 A / D converter (functional part)
41 AC / DC constant voltage power supply (power supply)
42 Cradle output connector (connector)
43 Voltage Detection Unit 44 Current Detection Unit 45 Charging Control Unit 61 Charging Circuit 62 Connection Switching Unit 63 Voltage Detection Unit 64 Charging Control Circuit 100 Radiographic Imaging System V1 to V3 Target Voltages ΔV1, ΔV2, ΔV3, ΔV11, ΔV12, ΔV13 Voltage Change amount

Claims (7)

A charging device that charges the power storage unit from the outside of the housing through a connector provided between the radiographic imaging device having a power storage unit that supplies power to each functional unit inside the housing. And
A power supply unit for supplying power for charging the power storage unit;
A voltage detection unit for detecting a voltage of the power storage unit;
A current detection unit for detecting a charging current flowing through the power storage body during the charging;
A constant current charging is performed until the voltage of the power storage unit detected by the voltage detection unit reaches a target voltage, and a charge control unit that switches to constant voltage charging when the voltage of the power storage unit reaches the target voltage,
The charge controller is
Changing the charging current between at least two values at the start of the constant current charging and detecting the voltage change of the power storage unit accompanying the current change by the voltage detection unit;
A charging apparatus for a radiographic imaging apparatus, wherein charge control is performed by correcting a value of the target voltage or a detection voltage of the voltage detection unit according to a change amount of the voltage of the power storage unit. The charge controller is
While changing the charging current multiple times at the start of the constant current charging and individually detecting the voltage change of the power storage unit accompanying the change of the respective charging current,
The charge control is performed by correcting a value of the target voltage or a detection voltage of the voltage detection unit in accordance with a change amount of the voltage of the power storage body due to the change of the current value a plurality of times. The charging device of the radiographic imaging apparatus of 1. The charge controller is
The electric resistance from the voltage detection unit to the power storage unit is obtained from the current change amount at the start of the constant current charging and the voltage change amount of the power storage unit detected by the voltage detection unit with the current change. , To determine the error amount of the detection voltage in the voltage detection unit due to the electrical resistance,
3. The charging apparatus for a radiographic imaging apparatus according to claim 1, wherein charging control is performed by correcting a value of the target voltage or a detection voltage of the voltage detection unit based on the error amount. A radiographic imaging device that houses a power storage unit that supplies power to each functional unit inside the housing, and the radiographic imaging device from the outside of the housing to the power storage unit through a connector provided between the radiographic imaging device. A radiological image detection system comprising a charging device for charging,
The charging device is:
A power supply unit for supplying power for charging the power storage unit;
A voltage detection unit for detecting a voltage of the power storage unit;
A current detection unit for detecting a charging current flowing through the power storage body during the charging;
A constant current charging is performed until the voltage of the power storage unit detected by the voltage detection unit reaches a target voltage, and a charge control unit that switches to constant voltage charging when the voltage of the power storage unit reaches the target voltage,
The charge controller is
Changing the charging current between at least two values at the start of the constant current charging and detecting the voltage change of the power storage unit accompanying the current change by the voltage detection unit;
A radiographic image detection system that performs charge control by correcting a value of the target voltage or a detection voltage of the voltage detection unit according to a change amount of the voltage of the power storage unit. The radiographic imaging device includes a backflow prevention circuit that blocks connection with the power storage unit unless a predetermined open circuit voltage is applied from the outside.
The charge controller is
At the start of the constant current charging, the charging current is changed between at least two values that allow voltage application higher than the open circuit voltage, and the voltage change of the power storage unit due to the current change is detected by the voltage detection unit. ,
The radiographic image detection system according to claim 4, wherein charge control is performed by correcting a value of the target voltage or a detection voltage of the voltage detection unit according to a change amount of the voltage of the power storage unit. The charge controller is
While changing the charging current multiple times at the start of the constant current charging and individually detecting the voltage change of the power storage unit accompanying the change of the respective charging current,
The charge control is performed by correcting a value of the target voltage or a detection voltage of the voltage detection unit in accordance with a change amount of the voltage of the power storage body due to the change of the current value a plurality of times. The radiation image detection system according to 4 or 5. The charge controller is
The electric resistance from the voltage detection unit to the power storage unit is obtained from the current change amount at the start of the constant current charging and the voltage change amount of the power storage unit detected by the voltage detection unit with the current change. , To determine the error amount of the detection voltage in the voltage detection unit due to the electrical resistance,
The radiographic image detection system according to any one of claims 4 to 6, wherein charge control is performed by correcting a value of the target voltage or a detection voltage of the voltage detection unit based on the error amount.

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