JP2011147263A - System and method for charging electric double-layer capacitor, and radiation image detecting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a system and method for charging an electric double-layer capacitor, capable of charging the electric double-layer capacitor as fast as possible until its voltage reaches a given voltage in a quick, safe manner, and to provide a radiation image detecting device. <P>SOLUTION: The charging system for the electric double-layer capacitor 28 includes: a charge current value selecting unit 72 for selecting a first current value as a current value of a charge current until a voltage value of the electric double-layer capacitor 28 determined by a charge voltage determiner 71 reaches a given target voltage equal to or less than a predetermined voltage, and for selecting a second current value lower than the first current value as a current value of the charge current when the voltage value of the electric double-layer capacitor 28 reaches the given target voltage; and a charge current switching unit 73 which switches the current value of the charge current in accordance with a current value selection made by the charge current value selecting unit 72. Thereby, the charging system charges the electric double-layer capacitor 28 with a constant current while keeping the voltage value thereof at the predetermined voltage or below. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an electric double layer capacitor charging system, an electric double layer capacitor charging method, and a radiation image detection apparatus.

Conventionally, rechargeable secondary batteries such as nickel cadmium batteries, nickel metal hydride batteries, lithium ion batteries, small sealed lead batteries, lead storage batteries, etc. have been generally used as batteries for various devices. It takes a long time to charge.
For this reason, in recent years, it has been considered to use an electric double layer capacitor capable of high-speed charging as a battery.

For example, a radiation image detection device called a flat panel detector (FPD), which is a means for acquiring medical radiation images, has recently been built into a portable type that has a built-in battery and can be driven without a cable. A configured cassette-type radiation image detection apparatus has been developed.
When the radiological image detection apparatus is configured to be portable, it is possible to perform imaging with a high degree of freedom including portable imaging on the patient's bedside or the like.
In order to make full use of the merits of such a portable radiological image detection apparatus, it is desired to adopt a battery that can be used for a long time and can be charged at high speed. An electric double layer capacitor is expected as a battery to satisfy.

Unlike the secondary battery using a chemical reaction, the electric double layer capacitor has a low internal resistance (for example, the internal resistance of the lithium ion secondary battery is 20 to 100 mΩ, whereas the internal resistance of the electric double layer capacitor is 1). Therefore, charging / discharging with a high current is possible.
For this reason, it is possible to charge in a short time by charging to a specified voltage in consideration of a voltage drop due to a resistance component at a constant high charging current value.

However, on the other hand, high current charging can be performed, but voltage drop due to resistance components inside the semiconductor switch and the electric double layer capacitor is large.
That is, according to Ohm's law, the voltage drop is a value obtained by multiplying the charging current value by the resistance component. For example, if the charging current value is 1 A and the resistance component is 200 mΩ, 1 × 0.2 = 0.2V. A voltage drop will occur.

In addition, the voltage drop value is highly dependent on the current value of the charging current and the device temperature (environmental temperature), and the difference between the low current / low temperature and the high current / high temperature is several hundred mV. Also reach. For this reason, there is a problem that a large variation occurs in the voltage value after the completion of charging after charging to the specified voltage.
In this regard, if the environmental temperature can be kept constant, the value of the voltage drop can be accurately predicted and charging can be performed in consideration of that amount. However, it is difficult to control the environmental temperature because the change in the environmental temperature is greatly affected by the heat generated in the charging circuit itself due to charging with a high current value.

Therefore, in order to accurately charge the electric double layer capacitor to a working voltage (for example, rated voltage), it is conceivable to perform constant voltage charging after constant current charging until the rated voltage is reached.
In addition, when charging an electric double layer capacitor with a constant current power supply, it is overcharged for a predetermined time to a predetermined set voltage value exceeding the working voltage (for example, rated voltage) of the electric double layer capacitor in consideration of the voltage drop beforehand. It has been proposed (see, for example, Patent Document 1).
In this way, if overcharging is performed to a voltage value exceeding the operating voltage, it is possible to achieve a desired voltage level without performing constant voltage charging after constant current charging, so that charging can be performed at high speed. .

JP-A-7-57978

However, when charging is performed by combining constant current charging and constant voltage charging with high current, there are several residuals from the voltage after completion of charging with high current charging to the working voltage (for example, rated voltage) of the electric double layer capacitor. In the case of 100 mV, the charging time required to reach a working voltage (for example, rated voltage) by subsequent constant voltage charging may reach several times the constant current charging time.
In addition, when charging the electric double layer capacitor, since the variation of the voltage value after the completion of charging is large as described above, when the charging is surely performed up to the rated voltage by the method described in Patent Document 1, this variation. It is necessary to charge to a voltage that greatly exceeds the rated voltage in consideration of the minute.
In this respect, the upper limit of the charging voltage of the electric double layer capacitor is strictly defined from its reliability, and there is a problem that application of a voltage higher than the rated voltage causes deterioration of characteristics.
In addition, there is a problem in that, when charging is performed to a voltage that greatly exceeds a desired specified voltage (rated voltage) in consideration of the variation, a large variation occurs in the charging voltage due to individual differences.

  Therefore, the present invention has been made in view of the above circumstances, and an electric double layer capacitor charging system capable of charging an electric double layer capacitor to a predetermined voltage as quickly and safely as possible, It is an object of the present invention to provide a method for charging an electric double layer capacitor and a radiation image detection apparatus.

In order to solve the above-described problem, the electric double layer capacitor charging system of the present invention includes:
An electric double layer capacitor charging system for charging an electric double layer capacitor to a predetermined specified voltage,
Charging for selecting a current value of the charging current suitable for charging according to a voltage value of the electric double layer capacitor, wherein a plurality of current values can be selected as a current value of a charging current for charging the electric double layer capacitor Current value selection means;
Charging current value switching means for switching the power supplied from the external power source to the current of the current value selected by the charging current value selecting means;
Voltage value determining means for determining a voltage value of the electric double layer capacitor,
The charging current value selection means sets the first current value until the voltage value of the electric double layer capacitor determined by the voltage value determination means reaches a predetermined target voltage equal to or lower than the predetermined specified voltage. When the voltage value of the electric double layer capacitor selected as a value and determined by the voltage value determination means becomes the predetermined target voltage, a second current value lower than the first current value is set as the current of the charging current. The charging current value switching means switches the current value of the charging current according to the selection by the charging current value selection means, so that the voltage value of the electric double layer capacitor exceeds the predetermined specified voltage. It is characterized by constant current charging with no limit.

An electric double layer capacitor charging method according to another aspect of the present invention is as follows.
An electric double layer capacitor charging method for charging an electric double layer capacitor to a predetermined specified voltage,
Charging until the voltage value of the electric double layer capacitor becomes a predetermined target voltage equal to or lower than the predetermined specified voltage by a charging current of a first current value;
After the voltage value of the electric double layer capacitor reaches the predetermined target voltage, the voltage value of the electric double layer capacitor is set to the predetermined target by a charging current having a second current value lower than the first current value. Charging to a voltage, and
Constant current charging is performed as long as the voltage value of the electric double layer capacitor does not exceed the predetermined specified voltage.

A radiological image detection apparatus according to another aspect of the present invention is provided.
An electric double layer capacitor that supplies power to each functional unit;
A power supply connector for receiving power supplied from an external power source;
Charging control means provided on a charging path between the power feeding connector and the electric double layer capacitor;
Voltage value determining means for determining a voltage value of the electric double layer capacitor;
With
The charge control means includes
Charging for selecting a current value of the charging current suitable for charging according to a voltage value of the electric double layer capacitor, wherein a plurality of current values can be selected as a current value of a charging current for charging the electric double layer capacitor Current value selection means;
Charging current value switching means for switching the power supplied from the external power source to the current of the current value selected by the charging current value selection means,
The charging current value selection means sets the first current value until the voltage value of the electric double layer capacitor determined by the voltage value determination means reaches a predetermined target voltage equal to or lower than the predetermined specified voltage. When the voltage value of the electric double layer capacitor selected as a value and determined by the voltage value determination means becomes the predetermined target voltage, a second current value lower than the first current value is set as the current of the charging current. The charging current value switching means switches the current value of the charging current according to the selection by the charging current value selection means, so that the voltage value of the electric double layer capacitor exceeds the predetermined specified voltage. It is characterized in that the current value of the charging current supplied to the electric double layer capacitor is controlled so that constant current charging is performed with no limit.

According to the present invention, constant current charging is performed with the first current value until the voltage value of the electric double layer capacitor reaches a predetermined target voltage or a predetermined target voltage lower than the predetermined voltage, and the voltage value is a predetermined predetermined voltage or When a predetermined target voltage is reached, constant current charging is performed with a second current value lower than the first current value.
For this reason, it is possible to perform charging so that the voltage value of the electric double layer capacitor does not exceed the specified voltage while shortening the charging time by high-speed charging with high current, and charging to the specified voltage safely and reliably. There is an effect that you can.

It is a principal part block diagram which shows the functional structure of charge control of the radiographic image detection apparatus which concerns on this embodiment. It is a perspective view which shows the external appearance of the radiographic image detection apparatus shown in FIG. FIG. 2 is an equivalent circuit diagram illustrating configurations of a sensor panel unit, a reading unit, and the like of the radiological image detection apparatus illustrated in FIG. 1. It is explanatory drawing which shows the change of the charging current and charging voltage of charge in this embodiment. It is explanatory drawing which shows the change of the charging current and charging voltage of charge in the modification of this embodiment. It is explanatory drawing which shows the change of the charging current and charging voltage of charge in the modification of this embodiment.

  Hereinafter, preferred embodiments of an electric double layer capacitor charging system (hereinafter simply referred to as a charging system), an electric double layer capacitor charging method, and a radiation image detection apparatus according to the present invention will be described with reference to FIGS. Will be described. Note that embodiments to which the present invention is applicable are not limited to this.

FIG. 1 is a block diagram schematically illustrating a main configuration of charge control of a radiation image detection apparatus including a charging system according to the present embodiment.
In this embodiment, the radiation image detection apparatus 2 is a portable cassette type FPD in which a so-called flat panel detector (hereinafter referred to as “FPD”) is configured as a cassette type, and is used for radiographic imaging. Image data (hereinafter simply referred to as “image data”) is acquired.
In the following, a so-called indirect radiation image detection device 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 detection device 2. However, the present invention can also be applied to a so-called direct radiation image detection apparatus that directly detects radiation with a radiation detection element without using a scintillator or the like.

The radiological image detection apparatus 2 is provided with an electric double layer capacitor 28 as a battery that supplies power to each functional unit of the radiographic image detection apparatus 2.
The electric double layer capacitor 28 can be used at a charging voltage between 2 V and 4 V, for example, and has a low internal resistance, so that high-speed charging can be performed with a charging current having a high current value such as 5 A to 10 A, for example. .
In the present embodiment, the electric double layer capacitor 28 widely includes power storage elements such as a lithium ion capacitor (LIC).

  The radiation image detection apparatus 2 is supplied with power from an external power source (not shown) (in this embodiment, the external power source is a constant current power source) via an external power supply means (cradle 4 or power supply cable 5). The radiological image detection apparatus 2 includes a power feeding connector 26 that receives power from the external power source.

  The radiological image detection apparatus 2 according to the present embodiment uses a current suitable for charging the electric double layer capacitor 28 as a charging path between the power supply connector 26 and the electric double layer capacitor 28. A first charging path 65a (shown by a solid line in FIG. 1) that is supplied to the electric double layer capacitor 28 after being converted into a charging current of a value, and the power supplied from the outside is used as it is (voltage value and current value are converted into a radiographic image). Two types of charging paths 65b (indicated by broken lines in FIG. 1) for supplying the electric double layer capacitor 28 (without conversion on the detection device 2 side) are provided.

The external power supply means connected to the radiation image detection apparatus 2 according to the present embodiment includes a power supply cable 5 and a cradle 4, and any one of the power supply cable 5 and the cradle 4 is used for power supply in the radiation image detection apparatus 2. A connection determination unit 60 that determines whether the connector 26 is connected and a charging path switching unit 63 that switches the charging path according to the determination result are provided.
The connection determination means 60 includes a voltage detection unit 61 that detects a voltage value of power supplied from the power supply connector 26, and a power supply cable connected to the power supply connector 26 according to the level of the voltage value detected by the voltage detection unit 61. 5 and an input voltage determination circuit 62 for detecting and determining which of the cradle 4 is connected. For example, the input voltage determination circuit 62 determines whether or not the voltage value detected by the voltage detection unit 61 is higher than a reference value. If the voltage value is higher than the reference value, the input voltage determination circuit 62 determines that the power feeding cable 5 is connected. If it is lower than the reference value, it is determined that the cradle 4 is connected.

  In the present embodiment, the configuration is such that either the power supply cable 5 or the cradle 4 is detected and determined by detecting the voltage of the power supplied to the power supply connector 26, but the connection determination means 60. There is no particular limitation on the detection / determination method based on, and other methods may be used.

The charging path switching means 63 is a switch that is switched ON / OFF by applying a predetermined voltage, for example.
In the present embodiment, when it is determined by the input voltage determination circuit 62 that the power supply cable 5 is connected to the power supply connector 26, the charging path switching means 63 switches the charging path to be the first charging path 65a. . When the input voltage determination circuit 62 determines that the cradle 4 is connected to the power supply connector 26, the charging path switching unit 63 switches the charging path to the second charging path 65b. Yes.
Note that the determination method by the connection determination unit 60 and the control method of the charging path switching unit 63 are not limited to those exemplified here.

An internal charging control circuit 70 and an internal charging circuit 75 are provided on the first charging path 65a. In the present embodiment, the internal charging control circuit 70 and the internal charging circuit 75 constitute the charging system 1 that charges the electric double layer capacitor 28.
The internal charging control circuit 70 converts the power supplied from the external power source via the power supply cable 5 into a voltage / current suitable for charging the electric double layer capacitor 28. The charging voltage determination unit 71, the charging current A value selection unit 72, a charging current value switching unit 73, a constant voltage charging switching unit 74, and the like are provided.
The charging voltage determination unit 71 is a charging voltage value determination unit that detects and determines the voltage value of the electric double layer capacitor 28.

The electric double layer capacitor 28 functions normally within a predetermined voltage value range. For example, when the rated voltage value is 4 V and the minimum voltage value is 2 V, the voltage value of the electric double layer capacitor 28 is If the battery is charged to a point where the voltage exceeds the rated voltage of 4 V, the characteristics deteriorate.
Further, the electric double layer capacitor 28 has a characteristic of approaching a neutral voltage (a natural voltage on physical properties) if it is normal. Therefore, when the voltage value of the electric double layer capacitor 28 does not recover below a minimum voltage value (for example, 2V), it is estimated that the electric double layer capacitor 28 is not functioning normally. In this case, it is necessary to replace the electric double layer capacitor 28. If charging is performed in this state, there is a risk of damage or the like.
Therefore, the charging voltage determination unit 71 detects and determines the voltage value of the electric double layer capacitor 28 and outputs the determination result to the internal charging control circuit 70.

If the voltage value of the electric double layer capacitor 28 is lower than the minimum voltage value based on the determination result by the charging voltage determination unit 71, charging is prohibited and a warning is given by the control unit 30 (see FIG. 3). It is preferable that notification is made by display (for example, blinking of an indicator 25 (see FIG. 2) described later) or a warning sound.
Further, the determination by the charging voltage determination unit 71 is not limited to charging. For example, if the remaining amount of the electric double layer capacitor 28 becomes insufficient during the photographing, it is inconvenient because the photographing needs to be performed again. Therefore, the remaining amount of the electric double layer capacitor 28 is referred to by referring to the determination result by the charging voltage determination unit 71. When it is determined that the image is not enough to shoot one image, the control unit 30 (see FIG. 3) displays a warning (for example, blinking of an indicator 25 (see FIG. 2) described later) or a warning sound. It is preferable that notification is made.

  The charging current value selection unit 72 can select a plurality of current values as the current value of the charging current for charging the electric double layer capacitor 28, and the electric double layer capacitor 28 detected and determined by the charging voltage determination unit 71. Charging current value selection means for selecting a current value of a charging current suitable for charging according to the voltage value.

  In the present embodiment, the charging current value selection unit 72 has a high current value (for example, 10A) (eg, the first current) until the voltage value of the electric double layer capacitor 28 reaches a predetermined target voltage equal to or lower than a predetermined specified voltage. Is selected as the current value of the charging current, and when the voltage value of the electric double layer capacitor 28 reaches a predetermined target voltage, the current value is lower than the first current value (for example, 3 A, etc.). Is selected as the current value of the charging current.

  Here, the predetermined specified voltage refers to a case where the user arbitrarily sets a voltage value lower than the withstand voltage as well as the rated voltage as the withstand voltage displayed on the electric double layer capacitor 28. It is a concept including a voltage value. For example, when the rated voltage (withstand voltage) displayed on the electric double layer capacitor 28 is 4V, but is not used up to 4V as a user's application, the voltage value for completing charging is a voltage lower than the rated voltage. When a value (for example, 3.5 V) is set and used up to 3.5 V, this voltage value (3.5 V) is the specified voltage in this embodiment.

The predetermined target voltage is a voltage value that is the same as or lower than the predetermined specified voltage. Since the characteristics of the electric double layer capacitor 28 deteriorate when the voltage value exceeds the rated voltage, it is preferable to stop the charging when the rated voltage is reached or just before the rated voltage is reached. . In addition, when the user arbitrarily sets a specified voltage lower than the rated voltage, it is not preferable to charge beyond this because it wastes power.
Therefore, in this embodiment, a voltage value that is the same as or slightly lower than the specified voltage (that is, the rated voltage of the electric double layer capacitor 28 or a voltage arbitrarily determined by the user) is determined as the target voltage, and the electric double layer When the voltage value of the capacitor 28 reaches this target voltage, control is performed so as to stop charging.

  Note that whether to stop charging when the specified voltage is reached or whether a lower voltage value is set as the target voltage and charging is stopped when reaching the target voltage may be determined in advance. However, it may be set by the user.

The charging current value switching unit 73 is a charging current value switching unit that switches the power supplied from the external power source to the current having the current value selected by the charging current value selection unit 72, and is, for example, a semiconductor switch. The charging current value switching unit 73 is not limited to a semiconductor switch as long as the current value can be switched.
In the present embodiment, for example, when the first current value is selected by the charging current value selection unit 72, the charging current value switching unit 73 uses a charging current having a high current value, such as 10 A, supplied from the external power source. When the second current value is selected by the charging current value selection unit 72, the electric power supplied from the external power source is converted into a charging current having a low current value such as 3A and the electric double layer capacitor 28 It has come to offer.

When constant current charging is performed with a charging current having a high current value, charging can be performed in a short time. On the other hand, voltage drop caused by a resistance component in the semiconductor switch or the electric double layer capacitor 28 may occur. growing.
That is, according to Ohm's law, the voltage drop is a value obtained by multiplying the charging current value by the resistance component. For example, if the current value of the charging current is 1 A and the resistance component is 200 mΩ, then 0.2 V (ie, 1 × 0.2 = 0.2V) voltage drop occurs.
In this respect, when the current value of the charging current is switched to 0.1 A, the voltage drop can be suppressed to 0.02 V (that is, 0.1 × 0.2 = 0.02 V).
For this reason, once the voltage value of the electric double layer capacitor 28 reaches a predetermined target voltage, constant current charging with a charging current having a low current value is performed, so that the voltage drop is limited to a predetermined specified voltage while keeping the voltage drop low. The battery can be reliably charged to a close value.

In addition, the constant voltage charge switching unit 74 performs constant voltage charge to switch to constant voltage charge after the voltage value of the electric double layer capacitor 28 reaches a predetermined target voltage by constant current charge with a second current value (for example, 3A). Switching means.
In the case of constant voltage charging, since the current value decreases as the voltage value increases, charging can be performed to the limit of the target voltage (for example, rated voltage).
The constant voltage charging requires time compared to the constant current charging with a high current value, but the constant current charging with the charging current with a low current value is performed first, and the electric double layer capacitor 28 is brought close to a predetermined specified voltage value. By switching to constant voltage charging after increasing the voltage value, charging up to a specified voltage can be realized without lengthening the time required for charging so much.

  The internal charging circuit 75 is a circuit for safely supplying the current value of the charging current to the electric double layer capacitor 28 while maintaining the charging current value selected and set by the internal charging control circuit 70.

  On the other hand, when the second charging path 65b is selected by the input voltage determination circuit 62 and is switched to the second charging path 65b, the input voltage determination circuit 62 supplies the radiation image detection apparatus 2 from the cradle 4 via the power feeding connector 26. The electric power is supplied to the electric double layer capacitor 28 with the voltage value and the current value as they are (that is, with a high current value such as 5A to 10A).

  The cradle 4 as an external power supply means is configured to be able to supply power to the radiation image detection device 2 from the outside by mounting the radiation image detection device 2 and is connected to an external power source (not shown). An AC / DC power supply to which an outlet is connected and an output connector for outputting the power supplied from the AC / DC power supply to the outside are provided (none of which are shown). The AC / DC power supply outputs power at a constant voltage regardless of load fluctuations, and the output connector supplies power to the radiation image detection apparatus 2 at this predetermined voltage. ing.

In addition, the cradle 4 includes a connection detection / determination unit that detects and determines whether or not the output connector is connected to the power supply connector 26 of the radiation image detection apparatus 2 and a switch that switches whether or not to output power to the outside. Provided (none shown).
The method by which the connection detection / determination unit detects / determines the connection between the output connector and the power supply connector 26 is not particularly limited. For example, physical contact with the output connector 42 may be detected.
The type of switch is generally an FET (Field-Effect Transistor), but is not limited to this. For example, an electromagnetic switch (electromagnetic relay), a semiconductor switch (SSR), a photoelectric switch (Photo relay), etc. You may comprise either.

  In this embodiment, when the radiation image detection device 2 is mounted on the cradle 4, the output connector on the cradle 4 side is electrically connected to the power supply connector 26 of the radiation image detection device 2, and the AC / DC power supply is connected. Then, power (for example, a charging current having a high current value such as 10 A) for charging the electric double layer capacitor 28 is directly supplied from the external power source to the radiation image detection apparatus 2 (that is, without converting the voltage value and the current value). It has come to be.

  The power supply cable 5 is capable of supplying power to the radiation image detection device 2 from the outside by being connected to the radiation image detection device 2. One end side of the power supply cable 5 is connected to the power supply connector 26 of the radiation image detection apparatus 2, the other end side is connected to an AC / DC power source (not shown), and an external power source (not shown) is connected via an outlet (not shown). ). As a result, when one end of the power supply cable 5 connected to an outlet or the like is connected to the power supply connector 26 of the radiation image detection apparatus 2, power is supplied from the external power source to the radiation image detection apparatus 2. In this case, the power supplied via the power supply cable 5 has a high voltage and a small current value. As will be described later, the electric power supplied via the power supply cable 5 is converted into a voltage and current suitable for the electric double layer capacitor 28 to be charged in the internal charge control circuit 70 of the radiation image detection apparatus 2.

  It should be noted that between the power supply cable 5 and the external power source, as in the case of the cradle 4, it is detected and determined whether or not the output connector of the power supply cable 5 is connected to the power supply connector 26 of the radiation image detection apparatus 2. A connection detection / determination unit and a switch (both not shown) for switching whether to output power to the outside are provided. Note that the configurations of the connection detection / determination unit and the switch are the same as those provided in the cradle 4, and therefore the description thereof is omitted.

FIG. 2 is a perspective view of the radiation image detection apparatus 2 in the present embodiment.
As shown in FIG. 2, the radiation image detection 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.

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

  The power switch 22 switches on / off of the power supply of the radiation image detection apparatus 2, and by operating the power switch 22, the radiation image detection apparatus 2 is operated by an electric double layer capacitor 28 (see FIG. 1) described later. A signal instructing start and stop of power supply to each functional unit is output to the control unit 30 (see FIG. 3) described later. When the radiological image detection apparatus 2 is not used for imaging, the power consumption of the electric double layer capacitor 28 is suppressed by turning off the power (that is, stopping the power supply to each functional unit by the electric double layer capacitor 28). Can do.

The indicator 25 is composed of, for example, an LED or the like, and displays the remaining charge amount of the electric double layer capacitor 28, various operation states, and the like.
In the present embodiment, when the voltage value of the electric double layer capacitor 28 is lower than the minimum voltage value (for example, 2 V), the user is notified of charging prohibition of the electric double layer capacitor 28, necessity of replacement, etc. It may function as a means to do.

  Further, a lid member 50 that is opened and closed for replacement of the electric double layer capacitor 28 built in the housing 21 is provided on a side surface portion of the radiation image detection apparatus 2. Are embedded with an antenna device 51 for the radiological image detection device 2 to transmit and receive information to and from an external device in a wireless manner.

The power supply connector 26 is configured to be electrically connectable to each of the cradle 4 and the power supply cable 5 and is a connection unit that receives power supplied to the radiation image detection apparatus 2 from the outside.
As described above, when the output connector of the cradle 4 is connected to the power feeding connector 26, it becomes possible to supply the electric double layer capacitor 28 with a charging current having a high current value and perform rapid charging. When the power supply cable 5 is connected to the power supply connector 26, the electric power from the external power source is switched to a current value corresponding to the voltage value of the electric double layer capacitor 28 and supplied to the electric double layer capacitor 28. The capacitor 28 can be charged.

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 the present embodiment, a reading unit 45 (see FIG. 3) that is a reading unit that reads the output value of each photoelectric conversion element 23 of the sensor panel unit 24 by the 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 control unit 30 via the A / D conversion unit 40, and a digital image signal is output to the control unit 30. A storage unit 31 is connected to the control unit 30, and the control unit 30 stores the digital image signal sent from the A / D conversion unit 40 in the storage unit 31 as image data.

  The control unit 30 is a computer that includes a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and the like (not shown), and controls the radiation image detection apparatus 2 as a whole. In the present embodiment, the connection determining means on the charging path, the external charging voltage determining circuit, the internal charging voltage determining circuit, the internal charging control circuit, and the like are controlled.

The ROM stores a program for performing various processes in the radiation image detection apparatus 2 such as a real image data generation process, an offset correction value generation process, and a charging control process, and various control programs and parameters.
In the present embodiment, a control program for controlling which setting is switched based on a signal from the input voltage determination circuit 62 or the charge voltage determination unit 71 when the electric double layer capacitor 28 is charged is stored.
The control unit 30 reads a predetermined program stored in the ROM, develops it in a work area of the RAM, and the CPU executes various processes according to the program.
Alternatively, the control unit 30 may have parameters and be controlled by the control unit 30 without using the internal charge control circuit 70 of the charging system 1, or the setting may be switched in each charging system 1, It is also possible to monitor the state.

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 read values (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.

  Next, a method for charging the electric double layer capacitor in the present embodiment will be described with reference to FIG.

  When the power supply cable 5 or the cradle 4 is connected to the power supply connector 26 of the radiation image detection device 2, the voltage of the power supplied from the external power source is detected by the voltage detection unit 61 of the connection determination means 60, and the detection result Based on this, the input voltage determination circuit 62 determines whether the power supply cable 26 or the cradle 4 is connected to the power supply connector 26. Based on the determination result, the charging path switching unit 63 switches the charging path.

  That is, when the input voltage determination circuit 62 determines that the power supply cable 5 is connected to the power supply connector 26, the charging path switching unit 63 switches the charging path to the first charging path 65a. In this case, the voltage value of the electric double layer capacitor 28 is determined by the charging voltage determination unit 71, and when this value is a normal value (for example, 2V to 4V), the internal charging control circuit 70 sets the predetermined current value. The charging current is supplied to the electric double layer capacitor 28, and the electric double layer capacitor 28 is charged. Note that when the voltage value of the electric double layer capacitor 28 is at a level close to a specified voltage (for example, 4 V), the internal charging control circuit 70 may perform control so as not to charge.

  When charging is performed, first, the charging current value selection unit 72 selects a current value of a charging current suitable for charging according to the voltage value of the electric double layer capacitor 28. For example, when the voltage value of the electric double layer capacitor 28 is somewhat lower than a specified voltage (for example, 4V), a high current value (for example, 10A: first current value) is selected as the current value of the charging current, The electric power supplied from the external power source is switched to a current having a high current value (for example, 10 A) selected by the charging current value selection unit 72 in the charging current value switching unit 73. The current whose current value is switched by the charging current value switching unit 73 is supplied to the electric double layer capacitor 28 as a charging current, and constant current charging (high constant current charging) is performed with a charging current having a high current value (in FIG. 4). a).

Even after the start of charging, the voltage value of the electric double layer capacitor 28 is determined by the charging voltage determination unit 71, and when it is determined that the voltage value has reached a predetermined target voltage (that is, a specified voltage or a voltage value lower than this). The constant current charging with the high current charging current is stopped. At this time, the voltage value of the electric double layer capacitor 28 that has once increased to a predetermined target voltage (for example, the same voltage value as a specified voltage such as a rated voltage) decreases due to voltage drop (arrow b in FIG. 4).
Then, the charging current value selection unit 72 selects a current value (for example, 3A: second current value) lower than the high current value (first current value) as the current value of the charging current. When the current value is selected by the charging current value selection unit 72, the charging current value switching unit 73 switches the charging current to a low current value (for example, 3 A) selected by the charging current value selection unit 72. The current whose current value is switched by the charging current value switching unit 73 is supplied to the electric double layer capacitor 28 as a charging current, and constant current charging (low constant current charging) is performed with a charging current having a low current value (in FIG. 4). c).
In this case, since the current value of the charging current is low, the voltage drop after charging up to a predetermined target voltage (for example, the same voltage value as the specified voltage such as the rated voltage) is small because it is not easily affected by the environmental temperature and the operating condition. Can be suppressed.

Furthermore, when the voltage value of the electric double layer capacitor 28 reaches a predetermined target voltage by the constant current charging with the charging current with the low current value, the constant current charging with the charging current with the low current value is stopped.
Then, switching to constant voltage charging is performed by the constant voltage charging switching unit 74, and thereafter constant voltage charging is performed until a predetermined specified voltage is reached (d in FIG. 4). Thus, the charging voltage can be safely and reliably charged to the specified voltage (for example, the rated voltage) without exceeding the specified voltage (for example, the rated voltage). In the present embodiment, since charging to a predetermined target voltage is performed after charging to a predetermined target voltage by constant current charging with a charging current having a low current value, there is little residual up to the rated voltage when switching to constant voltage charging. For this reason, the time required to reach the rated voltage by constant voltage charging can be significantly shortened compared to the conventional case.

When the input voltage determination circuit 62 determines that the cradle 4 is connected to the power supply connector 26, the charging path switching unit 63 switches the charging path to the second charging path 65b.
In this case, the electric power supplied through the cradle 4 is supplied as it is (with a low voltage) to the electric double layer capacitor 28, and fast charging is performed.
In addition, even when charging from the cradle 4, by switching the charging voltage, the charging voltage can be safely and reliably charged to the specified voltage (for example, the rated voltage) without exceeding the specified voltage (for example, the rated voltage). It can be performed. In this case, the charging voltage may be determined in the cradle 4 or may be determined using the charging voltage determination unit 71 of the internal charging control circuit, and a signal corresponding to the determination result is sent to the cradle 4. May be.

As described above, according to the present embodiment, since most of the charging is performed by constant current charging (high constant current charging) using a charging current having a high current value, the charging time can be shortened.
In addition, after a high constant current charge, in order to perform a constant current charge (low constant current charge) with a charge current with a low current value lower than this, a voltage drop caused by the internal resistance of the electric double layer capacitor 28 is reduced. Can be small.
Then, the voltage value of the electric double layer capacitor 28 is once increased to a predetermined target voltage (for example, the same voltage value as the specified voltage such as a rated voltage) by such a low constant current charging with a small voltage drop, and then the constant current charging is performed. Therefore, the residual to the rated voltage is small, and the time required to reach the specified voltage (for example, the rated voltage) by constant voltage charging can be greatly shortened compared to the conventional case.
Furthermore, since charging is performed until a specified voltage (for example, rated voltage) is reached by constant voltage charging, charging up to the specified voltage can be reliably performed.

  Further, since the voltage value of the electric double layer capacitor 28 does not exceed a predetermined specified voltage (for example, a rated voltage) during charging, it is possible to avoid deterioration of the characteristics of the electric double layer capacitor 28 due to overcharging.

  Furthermore, since excessive charging in consideration of the voltage drop is not performed, charging can be completed without wastefully supplying charging current.

In the present embodiment, the charging system 1 configured to charge the electric double layer capacitor 28 is configured by the internal charging control circuit 70 and the charging voltage determination unit 71 provided on the first charging path 65a. Although it was set as an example, the structure of the charging system 1 is not limited to this. For example, an internal charging control circuit 70 and a charging voltage determination unit 71 that constitute the charging system 1 may be provided inside the cradle 4.
In this case, the voltage value of the electric double layer capacitor 28 is determined inside the cradle 4, and the charging current obtained by appropriately converting the current value according to this is supplied from the cradle 4 to the power supply connector 26 of the radiation image detection apparatus 2. To be supplied.

In the present embodiment, when the charging voltage determination unit 71 determines that the voltage value of the electric double layer capacitor 28 is normal, a high current value is immediately selected as the current value of the charging current. Although the constant current charging (high constant current charging) is started with the charging current of the low current, as shown in FIG. You may make it perform the constant current charge (low constant current charge) by the charging current of a value.
In this case, first, a low constant current charge is performed for a certain period of time (e in FIG. 5), the state of the electric double layer capacitor 28 is confirmed, and if there is no problem, then a high current value is selected as the current value of the charging current. Then, constant current charging (high constant current charging) with a charging current having a high current value is started (f in FIG. 5). Then, when the voltage value of the electric double layer capacitor 28 has once increased to a predetermined target voltage (for example, the same current value as the rated voltage), the charging current value is switched to a lower current value again to perform low constant current charging. (G in FIG. 5).
If there is a problem with the state of the electric double layer capacitor 28, the electric double layer capacitor 28 may be damaged if a current having a high current value is suddenly supplied. In order to prevent such damage and the like, constant current charging (low constant current charging) with a charging current having a low current value for a certain period of time may be performed at the start of charging in order to confirm the state of the electric double layer capacitor 28. It is valid.

Further, in this embodiment, after performing low constant current charging with a charging current having a low current value, switching to constant voltage charging is performed for further constant voltage charging. However, as shown in FIG. 5, low constant current charging is performed. After performing, charging may be terminated without switching to constant voltage charging.
If the current value of the charging current is set to a low value, the voltage drop after the completion of charging is reduced correspondingly, and the specified voltage (rated voltage) can be sufficiently reached even with low constant current charging alone. In this case, the charging time can be shortened by completing the charging only by performing the low constant current charging after the high constant current charging and not performing the time-consuming constant voltage charging.

Further, in the present embodiment, an example has been described in which the charging current value selection unit 72 can select a first current value that is a high current value and a second current value that is a lower current value. However, the current value of the charging current that can be selected by the charging current value selection unit 72 is not limited to two types. A plurality of stages of current values may be selectable as the second current value lower than the first current value which is a high current value.
For example, when a three-stage current value can be selected as a low current value, as shown in FIG. 6, in order to see the state of the electric double layer capacitor 28 at the start of charging, a charging current having a low current value for a certain period of time is used. Then, constant current charging (low constant current charging) is performed (h in FIG. 6), and then switching to a high current charging current is performed to perform high-speed high constant current charging (i in FIG. 6). Then, low constant current charging is performed with a charging current having a current value as low as about half of the high current value (j in FIG. 6), and then low constant current charging is performed with a charging current having an extremely low current value (FIG. 6). 6) Ensure that the battery is charged to the specified voltage (rated voltage).
In addition, the number of times of switching the charging current, the type of charge current that can be selected, and the like are not particularly limited.
Further, it may be configured to automatically switch to a charging current having a predetermined current value after a predetermined time has elapsed. In this case, for example, a predetermined target voltage is set so as not to exceed the specified voltage, and the time until the target voltage is reached is set as the time for switching to the next current value.

  In the present embodiment, an example in which the charging system for the electric double layer capacitor 28 and the charging method for the electric double layer capacitor 28 are applied to charge the electric double layer capacitor 28 provided in the radiation image detection apparatus 2 has been described. However, the electric double layer capacitor to which the present invention can be applied is not limited to the one provided in the radiation image detection device 2, and the case where the electric double layer capacitor provided in various electronic devices, electric vehicles, etc. is charged. You may apply to.

  In addition, it is needless to say that the present invention is not limited to the above embodiment and can be modified as appropriate.

DESCRIPTION OF SYMBOLS 1 Charging system 2 Radiographic imaging device 4 Cradle 5 Power supply cable 24 Sensor panel part 25 Indicator 26 Power supply connector 28 Electric double layer capacitor 30 Control part 60 Connection determination means 61 Voltage detection part 62 Input voltage determination circuit 63 Charging path switching means 70 Internal charging control circuit 71 Charging voltage determination unit 75 Internal charging circuit 72 Charging current value selection unit 73 Charging current value switching unit 74 Constant voltage charging switching unit 65a First charging path 65b Second charging path

Claims (9)

An electric double layer capacitor charging system for charging an electric double layer capacitor to a predetermined specified voltage,
Charging for selecting a current value of the charging current suitable for charging according to a voltage value of the electric double layer capacitor, wherein a plurality of current values can be selected as a current value of a charging current for charging the electric double layer capacitor Current value selection means;
Charging current value switching means for switching the power supplied from the external power source to the current of the current value selected by the charging current value selecting means;
Voltage value determining means for determining a voltage value of the electric double layer capacitor,
The charging current value selection means sets the first current value until the voltage value of the electric double layer capacitor determined by the voltage value determination means reaches a predetermined target voltage equal to or lower than the predetermined specified voltage. When the voltage value of the electric double layer capacitor selected as a value and determined by the voltage value determination means becomes the predetermined target voltage, a second current value lower than the first current value is set as the current of the charging current. The charging current value switching means switches the current value of the charging current according to the selection by the charging current value selection means, so that the voltage value of the electric double layer capacitor exceeds the predetermined specified voltage. An electric double layer capacitor charging system characterized by constant current charging with no limit.   2. The electric double layer capacitor charging system according to claim 1, wherein the charging current value selecting unit is capable of selecting a plurality of stages of current values as the second current value.   A constant voltage charge switching means for switching to constant voltage charging is provided after the voltage value of the electric double layer capacitor reaches the predetermined target voltage by constant current charging with the second current value. The charging system for an electric double layer capacitor according to claim 1 or 2. An electric double layer capacitor charging method for charging an electric double layer capacitor to a predetermined specified voltage,
Charging until the voltage value of the electric double layer capacitor becomes a predetermined target voltage equal to or lower than the predetermined specified voltage by a charging current of a first current value;
After the voltage value of the electric double layer capacitor reaches the predetermined target voltage, the voltage value of the electric double layer capacitor is set to the predetermined target by a charging current having a second current value lower than the first current value. Charging to a voltage, and
A method of charging an electric double layer capacitor, comprising performing constant current charging as long as a voltage value of the electric double layer capacitor does not exceed the predetermined specified voltage.   5. The electric double layer capacitor charging method according to claim 4, wherein a plurality of stages of current values can be selected as the second current value.   6. The constant voltage charging is performed after the voltage value of the electric double layer capacitor reaches the predetermined target voltage by constant current charging with the second current value. Charging method of electric double layer capacitor. An electric double layer capacitor that supplies power to each functional unit;
A power supply connector for receiving power supplied from an external power source;
Charging control means provided on a charging path between the power feeding connector and the electric double layer capacitor;
Voltage value determining means for determining a voltage value of the electric double layer capacitor;
With
The charge control means includes
Charging for selecting a current value of the charging current suitable for charging according to a voltage value of the electric double layer capacitor, wherein a plurality of current values can be selected as a current value of a charging current for charging the electric double layer capacitor Current value selection means;
Charging current value switching means for switching the power supplied from the external power source to the current of the current value selected by the charging current value selection means,
The charging current value selection means sets the first current value until the voltage value of the electric double layer capacitor determined by the voltage value determination means reaches a predetermined target voltage equal to or lower than the predetermined specified voltage. When the voltage value of the electric double layer capacitor selected as a value and determined by the voltage value determination means becomes the predetermined target voltage, a second current value lower than the first current value is set as the current of the charging current. The charging current value switching means switches the current value of the charging current according to the selection by the charging current value selection means, so that the voltage value of the electric double layer capacitor exceeds the predetermined specified voltage. A radiological image detection apparatus, wherein a current value of a charging current supplied to the electric double layer capacitor is controlled so that constant current charging is performed with no limit.   The radiographic image detection apparatus according to claim 7, wherein the charging current value selection unit is capable of selecting a plurality of stages of current values as the second current value.   The charging control means includes constant voltage charging switching means for switching to constant voltage charging after the voltage value of the electric double layer capacitor reaches the predetermined target voltage by constant current charging with the second current value. The radiographic image detection apparatus according to claim 7 or 8, wherein

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