JP6688257B2 - Charged plate monitor - Google Patents

Description

  The present invention relates to a charged plate monitor device used for performance evaluation of an ion generator such as a static eliminator.

  For example, performance evaluation of an ion generator used for applications such as static elimination is generally performed using a charged plate monitor device (see, for example, Patent Document 1).

  This charging plate monitor device has a charging plate composed of a conductor plate of a predetermined size, which is arranged insulated from the ground portion, and measures the voltage of the charging plate (voltage generated between the charging plate and the ground portion). Is configured to be able to. In this case, the specifications such as the size of the charging plate, the capacitance value between the charging plate and the grounding part, the insulation characteristics of the charging plate, etc. shall be in accordance with the prescribed standard (IEC 61340-4-7 or JIS C 61340-4-7). , Is prescribed.

  When the performance evaluation of the ion generator is performed using such a charged plate monitor device, for example, while the charge plate charged to a high voltage of +1000 V (or −1000 V) is being discharged by the ion generator, , Measuring the time change of the voltage of the charging plate and measuring the time (decay time) required for the voltage of the charging plate to drop to +100 V (or -100 V), the operation of the ion generator (generation of ions). In general, a test such as measuring a fluctuation or offset of the voltage of the charging plate is generally performed in a state where (1) is continuously maintained.

JP-A-8-255668

  When the performance of the ion generator is evaluated using the charged plate monitor device, a high voltage of 1000 V or more is applied to the charged plate of the charged plate monitor device as described above. Therefore, in the conventional charged plate monitor, the voltage of the charged plate is generally measured by using the vibration capacitance type potential sensor. This oscillating capacitance type potential sensor is a sensor that converts the voltage of the charging plate into a low-voltage AC signal by vibrating the sensing unit.

  On the other hand, in recent years, due to the miniaturization of electronic devices such as semiconductor devices, the voltage resistance of the electronic devices has been reduced. Then, when the charge of an electronic device having low voltage resistance is removed, in order to prevent damage to the electronic device, it is induced in the electronic device due to the high voltage applied to the discharge electrode of the ion generator. It is required to reduce the induced voltage and the voltage generated in the electronic device by the generated positive and negative ions flowing into the electronic device as much as possible.

  In order to meet such demands, in recent ion generators, the generation frequency of positive and negative ions (the frequency of positive and negative high voltage applied to the discharge electrode) is higher than the conventional frequency (for example, 50 Hz or 60 Hz) (for example, several 100 Hz).

  However, if the performance evaluation of the ion generator having such a high frequency is performed by using the conventional charged plate monitor, the following inconvenience occurs.

  That is, in the conventional charged plate monitoring device, the vibration capacitance type potential sensor generally used for measuring the voltage of the charged plate has low frequency response performance, and the frequency of the voltage to be measured is, for example, 100 Hz. When it exceeds, the ratio (sensitivity) of the output voltage of the oscillating capacitance type potential sensor to the voltage of the measurement target becomes 3 dB or more lower than the ratio on the low frequency side of 100 Hz (see the broken line graph in FIG. 3). .

  Therefore, when performance evaluation of an ion generator with a frequency as high as several hundreds Hz is performed using a conventional charged plate monitor device, the measured value of the voltage of the charged plate by the vibration capacitance type potential sensor is actually measured. It tends to be lower than the voltage. As a result, the reliability of the test results of the performance evaluation of the ion generator tends to be low.

  The present invention has been made in view of such a background, and in a wide frequency range including a high frequency range, it becomes possible to accurately measure the voltage of the charging plate, and thus improve the reliability of the performance evaluation of the ion generator. An object of the present invention is to provide a charged plate monitor device that can be enhanced.

In order to achieve the above-mentioned object, the charged plate monitor device of the present invention has a predetermined capacitance in which the electrostatic capacity relating to the charged plate monitor device used for the performance evaluation of the ion generator is within the range defined by the JIS or IEC standard. The charged plate monitor device defined to be within a standard range,
A charging plate formed of a conductor plate of a predetermined size, which is arranged insulated from the grounding portion so as to form a capacitance between the grounding portion, and
A series connected to the charging plate and the grounding part so as to be connected in parallel to the capacitance of the space between the charging plate and the grounding part And a capacitive element group,
The capacitance values of the plurality of capacitance elements of the series capacitance element group are set such that the combined capacitance value of the capacitance value of the space between the charging plate and the ground portion is within a predetermined standard range. Cage,
A voltage generated by dividing the voltage generated between the charging plate and the ground portion by the series capacitance element group , the voltage varying at the ion generation frequency of the ion generator is grounded to the charging plate. It is characterized in that it is configured to generate as a measurement signal according to a voltage generated between the unit and the unit.

  In the present invention, the “capacity of the space between the charging plate and the ground portion” is specifically formed between the charging plate and the ground portion except for the series capacitive element group. It means the capacity of space. The “voltage divided by the series capacitive element group” is a part of the series capacitive element group (a number (<N) less than the total number N of capacitive elements connected in series in the series capacitive element group). Means the voltage across both ends of the element).

According to the above-mentioned present invention, by appropriately setting the capacitance values of the plurality of capacitance elements of the series capacitance element group, the combined capacitance value has a predetermined value within a range defined by the JIS standard or the IEC standard . The charged plate monitor device can be configured to have a value within the standard range.

Then, a voltage generated by dividing the voltage generated between the charging plate and the ground portion by the series capacitive element group , the voltage varying at the ion generation frequency of the ion generator is applied to the charging plate. Since it is generated as a measurement signal corresponding to the voltage generated between the ground portion and the ground portion, the voltage of the measurement signal is a signal having a voltage sufficiently smaller than the voltage generated between the charging plate and the ground portion. Can be

  Therefore, as a voltage measuring device for measuring the voltage of the measurement signal, a known general type that does not use an oscillating capacitance type potential sensor and can accurately measure a relatively low voltage in a wide frequency range including a high frequency range. Measuring instruments can be used. In addition, this type of measuring instrument generally has a high input impedance, and thus can effectively ensure the insulating property of the charging plate.

  Since such a voltage measuring device can be used, as a result, in the performance evaluation of the ion generator, the voltage of the charging plate (the voltage between the grounding portion) and the voltage are large, It is possible to measure accurately in a wide range of frequencies including the high frequency range.

  Therefore, according to the present invention, the voltage of the charging plate can be accurately measured in a wide frequency range including a high frequency range. As a result, it is possible to provide a charged plate monitor device capable of enhancing the reliability of the performance evaluation of the ion generator.

  Further, in the above-mentioned present invention, the series capacitive element group is arranged in a state of being shielded at a position apart from the charging plate so as to have a distance in the direction orthogonal to the normal direction of the charging plate. It is possible to adopt a mode in which it is performed.

  According to this, when performing the performance evaluation of the ion generator, it is possible to prevent the flow of the generated ions from being disturbed by the series capacitive element group or the like as much as possible.

  Further, in the present invention, the series capacitive element group and the amplifier or voltage measuring device for inputting the measurement signal are arranged with a grounded base interposed between the charging plate and the charging plate. It is also possible to adopt a mode in which the series capacitive element group and the amplifier or the voltage measuring device are shielded.

  According to this, since the series capacitive element group and the amplifier or the voltage measuring device can be arranged near the charging plate in a shielded state, the charging plate is prevented from being affected by disturbance noise as much as possible. It becomes possible to perform voltage measurement.

The figure which shows roughly the structure of the charging plate monitor apparatus of embodiment of this invention. FIG. 3 is a diagram showing a circuit configuration of the charged plate monitor device of the embodiment. 3 is a graph illustrating frequency characteristics of the charged plate monitor device according to the embodiment.

  An embodiment of the present invention will be described below with reference to FIGS. As shown in FIG. 1, a charging plate monitor device 1 of the present embodiment includes a charging plate 2 of a predetermined size, a series capacitive element group 10 configured by connecting a plurality of capacitive elements described below in series, and a serial capacitive element group 10 in series. A voltage measuring device 20 for measuring the voltage output from the capacitive element group 10.

  The charging plate 2 is composed of a rectangular conductor plate (for example, a metal plate) having a size of 150 mm × 150 mm.

  The charging plate 2 is supported on a plate-shaped conductive (for example, metal) base 3 grounded to the ground portion G via a plurality of (or single) insulating members 4, and the base is It is electrically insulated from the table 3 (and thus from the ground portion G). In this case, the charging plate 2 is arranged in a posture parallel to the surface of the base 3 so that the capacitance value C0 (see FIG. 2) of the space between the charging plate 2 and the ground portion G is substantially constant. There is. More specifically, the capacitance value C0 is a space formed between the charging plate 2 and the ground portion G (mainly the charging plate 2 and the normal direction of the charging plate 2 except for the series capacitive element group 10). In the capacitance value of the space (including the insulating member 4) formed between the ground portion G and the portion having the same potential (the base 3 in this embodiment), which is opposed to the charging plate 2. is there. The capacitance value C0 may include the capacitance between the cable (for example, the cable 13 described below) connected to the charging plate 2 and the ground portion G.

  Further, as shown in FIG. 1, a power source such as a DC power source 50 can be connected to the charging plate 2 via a connector 51 and a cable 52.

  Supplementally, the base 3 is not limited to the plate-shaped one, and may be, for example, a case-shaped one.

  In the present embodiment, the series capacitive element group 10 is configured by connecting, for example, two capacitive elements 11 and 12 in series, as shown in FIG. In this case, the respective capacitive elements 11 and 12 are composed of capacitors, for example. Each of the capacitive elements 11 and 12 may be configured by connecting a plurality of capacitors (for example, a plurality of capacitors connected in parallel). Further, each of the capacitive elements 11 and 12 may be composed of a capacitive element other than a capacitor.

  In the series capacitive element group 10, one end on the capacitive element 11 side is connected to the charging plate 2 via the cable 13 and the connector 14 as shown in FIG. 1, and the other end on the capacitive element 12 side is the ground portion G. Grounded to. As a result, the series capacitive element group 10 is connected in parallel to the capacitance of the space between the charging plate 2 and the ground portion G.

  Here, in the present embodiment, the capacitance value C0 of the space between the charging plate 2 and the ground portion G and the capacitance values C1 and C2 of the capacitance elements 11 and 12 configuring the series capacitance element group 10 are , Are preset with the following guidelines.

  That is, as described above, since the series capacitive element group 10 is connected in parallel with the capacitance of the space between the charging plate 2 and the ground portion G, the spatial capacitance and the series capacitive element group 10 are combined. The capacitance value Ci is given by the following equation (1).

Ci = C0 + (C1 × C2) / (C1 + C2) (1)

  Further, the voltage of the charging plate 2 (specifically, the voltage generated between the charging plate 2 and the ground portion G) is set to E, and the voltage E (hereinafter referred to as the plate voltage E) is set in the series capacitive element group 10. If a voltage obtained by dividing the voltage, for example, a voltage between both ends of the capacitance element 12 (a voltage between the midpoint between the capacitance elements 11 and 12 and the ground portion G) is Vout, Vout is expressed by the following equation (2 ).

Vout = E × C1 / (C1 + C2) (2)

  The voltage Vout corresponds to the measurement signal in the present invention. Since this voltage Vout is proportional to the plate voltage E as shown in the equation (2), it becomes possible to measure the plate voltage E as a result by measuring the voltage Vout.

  In the present embodiment, the capacitance values C0, C1, C2 are the predetermined capacitance values required by the charging plate monitor device 1 as the above-mentioned combined capacitance value Ci as the entire capacitance value between the charging plate 2 and the ground portion G. (Specifically, the condition that Ci falls within the range of 20 pF ± 2 pF) and the plate voltage E are the maximum voltage that can be applied to the charging plate 2 in the evaluation test of the ion generator (for example, 1000 V). ), The voltage Vout falls within a voltage (for example, a voltage of 200 V or less) that can be measured by using a voltage measuring device for low voltage measurement without using a vibration capacitance type potential sensor. Is set to satisfy the condition.

  As an example, the capacitance values C0, C1, C2 can be set such that the capacitance value C0≈3.3 pF, C1 = 17.4 pF, C2 = 460 pF (> C1). In this case, the combined capacitance value Ci calculated by the equation (1) is Ci≈20.0 pF, which is within the standard (within the range of 20 pF ± 2 pF). Further, the voltage Vout when the plate voltage E is set to 1000V is Vout≈36.4V according to the above equation (2), which is within a voltage of 200V or less.

  Table 1 below shows the results of measuring the combined capacitance value Ci using an LCR meter capable of measuring the capacitance value and the like when the capacitance values C0, C1, C2 are set as described above.

  As shown in Table 1 above, it was confirmed that the actual combined capacitance value Ci can be kept within the standard of 20 pF ± 2 pF in the frequency range of at least 10 kHz or less (frequency range of voltage applied to the charging plate 2). It was

  The voltage measuring device 20 is connected to the midpoint between the capacitive elements 11 and 12 of the series capacitive element group 10 via the cable 21 (shown in FIG. 1) in order to measure the voltage Vout. The voltage measuring device 20 is a general voltage measuring device of a type that does not use a vibration capacitance type potential sensor. The voltage measuring device 20 can measure a voltage in a relatively low voltage range (for example, a voltage in the range of −200V to + 200V) including the voltage Vout input from the series capacitive element group 10.

  As shown in FIG. 2, the voltage measuring device 20 includes an operational amplifier 20a connected to the voltage input section (input section of the voltage Vout) in the voltage follower format, and has an input impedance of a high input impedance of, for example, about 100 TΩ. It is a thing. Therefore, the current that can flow from the charging plate 2 to the voltage measuring device 20 can be made sufficiently small. As a result, the insulating property of the charging plate 2 is set to a predetermined standard (specifically, when the test voltage of 1000 V is applied to the charging plate 2, the standard is such that 10% or more of the test voltage should not be discharged within 300 seconds). Can be ensured to meet.

  Further, in the present embodiment, the voltage measuring device 20 employs a wide frequency band capable of accurately measuring the voltage. Therefore, the voltage Vout obtained by dividing the plate voltage E by the series capacitive element group 10 can be measured in a wide frequency range.

  The frequency characteristics that can be realized by the charged plate monitor device 1 of the present embodiment are illustrated in FIG. 3 as a graph of the example (solid line graph). Here, the “output / input ratio (relative value)” on the vertical axis of the graph of FIG. 3 is the voltage measured by the voltage measuring device 20 with respect to the voltage actually applied to the charging plate 2 from an external power source such as a function generator. It is the measured value of the ratio. The horizontal axis indicating frequency is a logarithmic axis.

  As shown in the figure, in the charged plate monitor device 1 of the embodiment (graph of the example), it was confirmed that the output / input ratio (relative value) can be kept constant in the frequency range of 10 kHz or less.

  Note that the broken line graph in FIG. 3 shows a conventional charged plate monitor device that is manufactured without the series capacitive element group 10 so that the capacitance value between the charged plate and the ground portion G falls within 20 pF ± 2 pF. It is a graph which illustrates the frequency characteristic at the time of measuring the applied voltage of a charging plate using an oscillating capacity type potential sensor. As shown in the figure, in the measurement using the oscillating capacitance type potential sensor, it is found that the output / input ratio (relative value) is greatly reduced in the high frequency range of 100 Hz or higher.

  Further, in the present embodiment, the voltage measuring device 20 and the series capacitive element group 10 are shielded by being housed inside the conductive shield case 40 which is grounded to the ground portion G, and at the same time, the charging plate 2 has the same structure. It is arranged at a position apart from the charging plate 2 to some extent so as to have a distance in a direction orthogonal to the normal direction. The shield case 40 may be made of, for example, a wire mesh, a metal plate, or a combination thereof. Further, the voltage measuring device 20 and the series capacitive element group 10 are arranged at positions having a distance from the charging plate 2 in the normal direction of the charging plate 2 in addition to the direction orthogonal to the normal direction of the charging plate 2. May be

  This prevents the flow of generated ions from being disturbed by the voltage measuring device 20 and the series capacitive element group 10 as much as possible when performing the performance evaluation of the ion generator W (shown by the chain double-dashed line in FIG. 2). is doing.

  The charged plate monitor device 1 of this embodiment is configured as described above. When the performance evaluation of the ion generator W is performed using the charged plate monitor device 1, as shown in FIG. 2, the DC power source 50 is connected to the charged plate 2 and the ion generator W is connected to the charged plate. It is arranged above the charging plate 2 with a predetermined space.

  Then, after applying a voltage of +1000 V (or −1000 V) or a voltage higher than that to the charging plate 2 from the DC power supply 50, the voltage is measured by the voltage measuring device 20 while operating the ion generator W. , Measuring the decay time until the voltage of the charging plate 2 decays from +1000 V (or −1000 V) to +100 V (or −100 V), or in a state where the ion generator W is steadily operated. By measuring the voltage with the voltage measuring device 20, a test such as observing a voltage fluctuation of the charging plate 2 or an offset is carried out.

  The charging plate monitor device 1 described above can be configured to satisfy a predetermined standard. Further, the voltage Vout (which is proportional to the plate voltage E) obtained by dividing the voltage (plate voltage E) of the charging plate 2 by the series capacitive element group 10 is input to the voltage measuring device 20, so that the charging plate 2 Even if a high voltage of ± 1000 V or a high voltage of more than 1000 V is applied to the voltage measuring device 20, the voltage Vout to be measured input to the voltage measuring device 20 can be set to a relatively low voltage.

  Therefore, as the voltage measuring device 20, a measuring device having a wide frequency band capable of performing accurate voltage measurement (a measuring device capable of performing accurate voltage measurement from a low frequency region to a high frequency region of about several tens kHz) may be adopted. it can. As a result, the ion generator W sets the generation frequency of positive and negative ions (the frequency of the positive and negative high voltage applied to the discharge electrode) to a low frequency of about 50 Hz or 60 Hz, and also the frequency to a high frequency such as several hundred Hz. It is possible to evaluate the performance of the ion generator W with high reliability, even if it is made into a new product.

  In the charging plate monitor device 1 of the present embodiment described above, the voltage measuring device 20 uses the voltage across the capacitive element 12 of the series capacitive element group 10 as the voltage Vout obtained by dividing the voltage of the charging plate 2. It was made to measure by. However, for example, the capacitance value C1 of the capacitance element 11 is set to be larger than the capacitance value C2 of the capacitance element 12, and the voltage across the capacitance element 11 is divided by the voltage of the charging plate 2. It is also possible to measure Vout with the voltage measuring device 20. However, in this case, since the potentials at both ends of the capacitive element 11 fluctuate, floating control for adjusting the reference potential is required.

  The number of capacitive elements connected in series in the series capacitive element group 10 may be three or more. In this case, between both ends of a series connection body (a series connection body of a part of the series capacitance element group 10) in which a smaller number (for example, two) of the capacitance elements connected in series are connected in series. Or the voltage across any one of the total number of capacitive elements connected in series can be used as the voltage Vout obtained by dividing the voltage of the charging plate 2. In this case, it is preferable that one end of the series connection body or one capacitive element that outputs the voltage Vout is connected to the ground portion G.

  Further, the charged plate monitor device 1 of the present embodiment is a device including the voltage measuring device 20, but the charged plate monitor device of the present invention is a device configured to use the voltage measuring device as an external device. May be

  Further, when the base 3 has a housing shape, one or both of the series capacitive element group 10 and the voltage measuring device 20 may be housed in the base 3. In this case, the base 3 can be used as a shield case.

  Further, for example, the base 3 is interposed between the series capacitive element group 10 and the voltage measuring device 20 or an amplifier (for example, an amplifier similar to the operational amplifier 20a) to which the voltage Vout is input, and the charging plate 2. The series capacitive element group 10 and the amplifier may be shielded while being arranged in this state (in other words, arranged on the back surface side of the base 3 (on the side opposite to the charging plate 2)).

  With this configuration, the series capacitive element group 10 and the voltage measuring device 20 or the amplifier can be arranged near the charging plate 2 in a shielded state, so that the charging plate 2 is protected from the influence of disturbance noise as much as possible. Voltage measurements can be made. In this case, when the base 3 has a housing shape, the series capacitive element group 10 and the voltage measuring device 20 or the amplifier may be housed in the base 3.

DESCRIPTION OF SYMBOLS 1 ... Charging plate monitor device, 2 ... Charging plate, 10 ... Series capacitance element group, 11, 12 ... Capacitance element, G ... Grounding part, 20 ... Voltage measuring device.

Claims (3)

The charged plate monitor device according to claim 1, wherein the electrostatic capacity of the charged plate monitor device used for performance evaluation of the ion generator is determined to be within a predetermined standard range which is a range defined by JIS standard or IEC standard. ,
A charging plate formed of a conductor plate of a predetermined size, which is arranged insulated from the grounding portion so as to form a capacitance between the grounding portion, and
A series connected to the charging plate and the grounding part so as to be connected in parallel to the capacitance of the space between the charging plate and the grounding part And a capacitive element group,
Capacitance values of a plurality of capacitive elements of the series capacitive element group is combined capacitance value of the capacitance value of the space between the charged plates and the ground portion are set to be a value within the specified range ,
A voltage generated by dividing the voltage generated between the charging plate and the ground portion by the series capacitive element group , the voltage varying with the ion generation frequency of the ion generator is generated as a measurement signal. A charged plate monitor device characterized by being configured. The charged plate monitor device according to claim 1,
The series capacitive element group is arranged in a shielded state at a position apart from the charging plate so as to have a distance in the direction orthogonal to the normal direction of the charging plate, with the series capacitive element group. Charge plate monitor device. The charged plate monitor device according to claim 1,
The series capacitive element group and an amplifier or a voltage measuring device for inputting the measurement signal are arranged with a grounded base interposed between the series capacitive element group and the series capacitive element group. And the amplifier or the voltage measuring device is shielded.