JP2013137222A - Static electricity discharge detection device, static electricity discharge detection method, and fluctuating electric field resistance inspection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect inductive ESD generated in an electronic device with high accuracy.SOLUTION: A static electricity discharge detection device G1 detects an inductive ESD phenomenon by a characteristic transient electromagnetic field generated following the inductive ESD phenomenon. A waveform analysis part G8 analyzes waveform characteristics of the transient electromagnetic field based on the detection signal of an antenna G5. A discharge determination part G80 determines, from the analysis result of the waveform analysis part G8, the presence of a discharge phenomenon based on whether the detection signal has broadband characteristics or repeated generation characteristics.

Description

  The present invention relates to a technique for detecting an electrostatic discharge phenomenon that occurs in an electronic device and its surroundings when, for example, a fluctuating electric field is exposed to the electronic device.

  As the integration density of semiconductor integrated circuit components increases, it has become difficult to maintain the strength (malfunction and breakdown resistance) of electronic devices including semiconductor components against electrostatic discharge. Semiconductor component manufacturers and electronic board manufacturers are improving their technology to control the effects of electrostatic discharge (ESD) within a safe range by using non-charging technology and ground reinforcement. However, it is often difficult to appropriately control static electricity in an actual use / operation environment.

  Conventionally assumed ESD is, for example, a discharge phenomenon that occurs between a conductive object such as a human body or the like when the electronic device comes into contact with the electronic device or when the conductive object is sufficiently close to the electronic device. . This ESD causes problems such as malfunction and damage of electronic devices, or triggers an ignition explosion in an explosive atmosphere.

  In addition, the ESD tolerance test in electronic devices is defined by the international standard IEC61000-4-2 and its related standards (ISO10605, JASO D101), etc., and generally used by an ESD test apparatus using an ESD gun. It has been. This ESD test apparatus makes the ESD gun contact terminal (discharge rod) contact the conductive part of the object to be measured, such as an electronic device with the power turned on, and pulls the ESD gun trigger switch. To generate contact discharge. When the surface of the object to be measured is an insulator, the contact terminal of the ESD gun with the trigger switch pulled is brought close to the object to be measured and discharged in the air. In any case, ESD is applied to the object to be measured from the outside, and its influence is observed. During the ESD test, it is checked whether or not the device under test operates normally, whether or not it returns to normal even if an instantaneous malfunction occurs.

  In some cases, a horizontal coupling plate and a vertical coupling plate are arranged around the object to be measured, and ESD is applied to them to test the resistance against indirect discharge.

Electrostatic discharge immunity test IEC61000-4-2

  Even an electronic device that has been tested in detail and strictly according to the above-mentioned international standard IEC61000-4-2 may cause a serious malfunction during, for example, the winter dry season. For example, automatic ticket gates in public transportation frequently malfunctioned during the winter, resulting in great confusion.

  The cause of this malfunction is not generally clarified. However, according to the new knowledge of the present inventors, which has not been known, when a person wearing clothing that is easily charged, such as chemical fiber, passes through an automatic ticket gate, the high-voltage electrostatic field generated from the charged clothing causes the insulation to occur. The components of the control circuit inside the covered ticket gate are inductively charged, and the charged charge is discharged to the nearby ground metal. Due to the electric discharge generated inside the electronic device, a strong transient electromagnetic wave is generated, which affects a control circuit at a close distance and induces a malfunction.

  For example, a similar malfunction may occur in a control panel of a control room such as a power plant, air traffic control, or chemical plant. An operator usually sits on a chair and operates the control panel, but when he stands up from the chair and tries to operate a high place, a malfunction occurs. The electrostatic capacity of the operator sitting in the chair is considered to be approximately 300 pF, but decreases to about 100 pF when standing up. When the amount of charge accumulated in the operator is constant, if the electrostatic capacity is reduced to one third, the potential of the operator jumps up to three times in an instant. Similar to the passing operation of the automatic ticket checker described above, this potential fluctuation of the operator may cause inductive charging in the components inside the control panel and induce a malfunction.

  In this specification, “an electrostatic discharge phenomenon caused by induction charging” is referred to as an “induction ESD phenomenon”.

  Therefore, it is extremely important to detect this induced ESD. For example, for various electronic devices, a strong electrostatic field is exposed to the inside of the electronic device before shipment to forcibly generate induced ESD, and a transient electromagnetic field due to this discharge is detected. An induced ESD tolerance test will be required to verify In addition, it monitors electronic devices that are actually in operation, such as control panels in power plants, air traffic control systems, and chemical plant control rooms, and monitors whether or not induced ESD has occurred. Prevention is also important. In such a case, there is a need for a device that reliably detects the induced ESD anyway.

  Incidentally, in the IEC61000-4-2 test using a conventional ESD test apparatus, it is impossible to detect induced ESD or evaluate resistance to induced ESD as described above. The ESD test based on the IEC standard is a direct discharge phenomenon that occurs when an electronic device (object to be measured) comes into contact with the outside (the human body to be operated) or an indirect phenomenon that occurs around the electronic device. This is to inspect the resistance to a general discharge phenomenon. Therefore, the occurrence of ESD can be visually recognized. However, in the above-described induced ESD, even if there is no visual discharge between the human body and the electronic device, a malfunction occurs due to the electrostatic discharge phenomenon that occurs quietly and violently inside the electronic device. Is not easy.

  In particular, recent electronic devices rarely use a metal plate for the case, and most of them are insulators such as plastic cases. When such an insulating case is used, since the electrostatic shielding effect is low, the voltage of the non-grounded conductor inside the electronic device changes greatly due to induction when the surrounding electrostatic field varies greatly. If the ground conductor is disposed through a narrow gap in the immediate vicinity of the non-ground conductor whose voltage has greatly changed, a spark discharge occurs due to dielectric breakdown of the gap between the two. For example, when the distance between the non-grounded conductor and the grounded conductor is 0.1 mm or less, spark discharge occurs at a potential difference of about 1000 V or less, for example, about 700 V when 0.05 mm. The discharge phenomenon in the non-grounded conductor inside the insulator due to such a fluctuating electrostatic field cannot be detected and evaluated by a conventional ESD test apparatus.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a technique capable of efficiently detecting induced ESD that is not assumed in a conventional ESD test apparatus or a normal discharge monitoring apparatus. Yes.

  The above object can be achieved by the following means based on the earnest studies of the inventors.

  That is, the present invention that achieves the above object is an electrostatic discharge detection device that analyzes a transient electromagnetic field characteristic of an induced ESD phenomenon, based on an antenna that detects the transient electromagnetic field, and a detection signal of the antenna. A waveform analysis unit that analyzes the waveform characteristics of the transient electromagnetic field, and the presence or absence of the induced ESD phenomenon based on whether the detection signal has a wideband characteristic or a repetitive generation characteristic based on the analysis result of the waveform analysis unit An electrostatic discharge detection device comprising: a discharge determination unit that determines

  In the electrostatic discharge detection apparatus, the waveform analysis unit further includes a first frequency analysis unit that determines whether the detection signal includes a first frequency component, and the detection signal includes the first frequency. A second frequency analysis unit that determines whether or not a second frequency component different from the component is included, wherein the discharge determination unit has substantially the same output waveform in the detection signal, When both of the second frequency components are included, it is determined that the induced ESD phenomenon exists.

  The electrostatic discharge detection device may further include a third frequency analysis unit that determines whether or not the detection signal includes a third frequency component different from the first and second frequency components, and the discharge determination The unit determines that the induced ESD phenomenon exists when the first, second, and third frequency components are included in substantially the same output waveform in the detection signal.

  In the electrostatic discharge detection apparatus, the first frequency and the second frequency are selected from an MF (medium wave) band, an HF (short wave) band, a VHF (ultra high wave) band, and a UHF (ultra-high frequency) band. It is characterized by being set to one band.

  In the electrostatic discharge detection device, the first frequency component and the second frequency component are further set to have a frequency difference of about 30 MHz or more.

  In the electrostatic discharge detection device, the waveform analysis unit further includes a repetitive waveform analysis unit that determines whether the detection signal includes a plurality of output waveforms, and the discharge determination unit includes the plurality of discharge determination units. It is characterized in that it is determined that the induced ESD phenomenon exists when the output waveform of the number of times is included.

  In the electrostatic discharge detection device, the repetitive waveform analysis unit further determines whether or not the detection signal includes a plurality of output waveforms that are a predetermined number of times or more, and the discharge determination unit is a predetermined number of times or more. When the plurality of output waveforms are included, it is determined that the induced ESD phenomenon exists.

  In the electrostatic discharge detection device, the waveform analysis unit further includes a polarity analysis unit that determines whether an output waveform included in the detection signal is a positive waveform or a negative waveform, and the repetitive waveform analysis unit includes: The number of occurrences is counted for each of the positive polarity waveform and the negative polarity waveform, and the discharge determination unit generates the positive polarity waveform a plurality of times or the negative polarity waveform occurs a plurality of times. If it is, it is determined that the induced ESD phenomenon exists.

  In the electrostatic discharge detection apparatus, the antenna is a monopole antenna.

  The present invention that achieves the above-described object provides an application electrode for exposing an electric field to an electronic device that is an object to be measured, and an electric field variation unit that varies the strength of the electric field applied to the electronic device during inspection. And the electrostatic discharge detection device according to any one of the above, and causing an induced ESD phenomenon in the electronic device by causing induction charging in the electronic device due to a change in the electric field during the inspection. An apparatus for inspecting fluctuation of electric field of electronic equipment, characterized in that the induced ESD phenomenon is detected by the electrostatic discharge detection device, and the operating characteristics of the electronic equipment are inspected based on the induced ESD phenomenon due to the induction charging. is there.

  In the fluctuating electric field tolerance inspection apparatus, the electric field fluctuating means further includes a voltage control device that fluctuates the strength of the electric field by changing a voltage applied to the application electrode.

  In the fluctuating electric field tolerance inspection apparatus, the electric field fluctuation means further causes the first induction charging to the electronic device by increasing an absolute value of the positive or negative electric field applied to the electronic device. Thereafter, the potential of the first induction charging of the electronic device is reset, and further, the absolute value of the positive or negative electric field is decreased, whereby the first induction charging and positive / negative are performed on the electronic device. Inverted second induction charging is generated.

  In the fluctuating electric field resistance inspection apparatus, the application electrode is a plate electrode, and a plane of the plate electrode is opposed to the electronic device.

  In the fluctuating electric field resistance inspection apparatus, the application electrode is a plate electrode, and an end face of the plate electrode is opposed to the electronic device.

  In the fluctuating electric field tolerance inspection apparatus, the electric field fluctuation means further includes a moving mechanism that changes a relative distance between the electronic device and the application electrode, and changes the strength and gradient of the electric field according to the change in the relative distance. It is characterized by making it.

  The fluctuating electric field tolerance inspection apparatus further includes synchronization control means for synchronizing the sensing timing of the electrostatic discharge detection apparatus and the electric field fluctuation timing by the electric field fluctuation means.

  The present invention for achieving the above object is an electrostatic discharge detection and detection method for analyzing a transient electromagnetic field characteristic of an induced ESD phenomenon, the step of detecting the transient electromagnetic field by an antenna, and a detection signal of the antenna. A waveform analysis step for analyzing the waveform characteristics of the transient electromagnetic field based on the analysis result of the waveform analysis step, and based on whether the detection signal has a broadband characteristic or a repetitive generation characteristic, An electrostatic discharge detection method comprising: a discharge determination step for determining presence or absence.

  In the discharge detection method, the waveform analysis step further includes a first frequency analysis step for determining whether or not the detection signal includes a first frequency component, and the detection signal includes the first frequency component. And a second frequency analysis step for determining whether or not a second frequency component different from the first frequency component is included, wherein the discharge determination step has substantially the same output waveform in the detection signal as the first and second output waveforms. When both of two frequency components are included, it is determined that the induced ESD phenomenon exists.

  According to the present invention, it is possible to detect the induced ESD with extremely high accuracy.

It is a figure which shows the experimental installation for verifying the discharge phenomenon detected by this invention. It is a graph which shows the discharge waveform detected by the experimental equipment. It is a graph which shows the relationship between the applied voltage and rise time of the same discharge waveform. It is a graph which compares the frequency spectrum envelope of a transient electromagnetic field, and the discrete electromagnetic waves (EMI) radiated | emitted with the operation | movement of an electronic circuit. It is a graph which shows the example of detection of multiple discharge. It is a block diagram which shows the example of 1 structure of the electrostatic discharge detection apparatus of this invention. It is a block diagram which shows the example of 1 structure of the electrostatic discharge detection apparatus of this invention. It is a graph which shows the detection signal waveform of two types of induction | guidance | derivation ESD sources (600V, 720V) received with a short monopole antenna. It is a graph which shows the result of having measured the frequency characteristic of a short monopole antenna. It is a front view which shows the main body apparatus of the test | inspection apparatus which concerns on 1st Embodiment of this invention. It is a top view which shows the main body apparatus of the test | inspection apparatus which concerns on 1st Embodiment of this invention. It is a side view which shows the main body apparatus of the test | inspection apparatus which concerns on 1st Embodiment of this invention. It is a figure which shows the control panel of the main body apparatus of the test | inspection apparatus which concerns on 1st Embodiment of this invention. It is a graph which shows the time fluctuation of the electric field waveform of the inspection device. It is a graph which shows the time fluctuation of the induction charge which arises with the electronic device of the inspection apparatus. It is a side view which shows the inspection apparatus which concerns on 2nd Embodiment of this invention. It is a top view which shows the inspection apparatus which concerns on 2nd Embodiment of this invention. It is a top view which shows the inspection apparatus which concerns on 3rd Embodiment of this invention. It is a side view which shows the inspection apparatus which concerns on 3rd Embodiment of this invention. It is a top view which shows the inspection apparatus which concerns on 4th Embodiment of this invention. It is a graph which shows the voltage control timing waveform of the test | inspection apparatus which concerns on 4th Embodiment of this invention. It is a figure which shows the other structural example of the same inspection apparatus. It is a figure which shows the other structural example of the same inspection apparatus. It is a figure which shows the other structural example of the same inspection apparatus. It is a figure which shows the other structural example of the same inspection apparatus. It is a side view which shows the inspection apparatus which concerns on 5th Embodiment of this invention. It is a front view which shows the inspection apparatus which concerns on 5th Embodiment of this invention. It is a figure which shows the inspection apparatus which concerns on 6th Embodiment of this invention. It is a figure which shows the inspection apparatus which concerns on 7th Embodiment of this invention. It is a figure which shows the other structural example of the same inspection apparatus. It is a figure which shows the other structural example of the same inspection apparatus. It is a figure which shows the other structural example of the same inspection apparatus. It is a figure which shows the other structural example of the same inspection apparatus.

  Exemplary embodiments of the present invention will be described in detail with reference to the drawings.

  First, an experiment conducted by the present inventors will be described. In this experiment, by applying a fluctuating electric field to the electronic device from the outside, the components inside the electronic device are inductively charged, and whether or not an electrostatic discharge phenomenon (inductive ESD) occurs inside the electronic device due to the induction charging. It verified about.

  FIG. 1 shows an experimental facility 1 for verification. In this experimental facility 1, two large and small copper plates 3 and 4 are arranged in a plastic case 2 with a gap of 0.05 mm. The gap is not limited to 0.05 mm, and may be about 0.5 mm depending on the level of the induced voltage. However, since the spark discharge is based on Paschen's law, it is better to be as narrow as possible. This is because if the atmospheric pressure is constant, the narrower the gap, the lower the voltage is discharged. Further, inside the plastic case 2, a distance of 20 mm is provided below the copper plates 3 and 4, and the coaxial cable 5 connecting the probe portion (tip portion) of the differential probe and the oscilloscope is parallel to the plastic case 2. It arrange | positions so that it may become, and the electromagnetic noise by the discharge phenomenon which generate | occur | produced between the copper plates 3 and 4 is detected. The separation distance 20 mm is not limited to this, and may be further separated as long as a sufficient reception voltage is generated. Specifically, the detection band of the differential probe is 400 MHz, and a digital oscilloscope 6 is connected to the coaxial cable 5 of the differential probe output to analyze the noise waveform detected during discharge. It should be noted that the signal input terminal at the tip of the differential probe, the + side and the − side are short-circuited with an extremely short copper wire to prevent input signals from entering. The large and small copper plates 3 and 4 are not grounded to the ground and are not in contact with surrounding conductors.

  In the verification, a fluctuating electric field generated by manually moving a charged Teflon (registered trademark) or plastic charging plate 7 from the right to the left or from the left to the right near the upper surface of the plastic case 2 is plastic. Applied to Case 2. A waveform detected by the digital oscilloscope 6 is shown in FIG. In this waveform, since the vibration has a period of 1 nanosecond or less and the amplitude is 10 V or more, a discharge is generated between the copper plates 3 and 4. As described above, since the input portion at the tip of the differential probe is short-circuited between the + side and the − side, no input signal is input to the differential probe. Accordingly, a signal having such a large amplitude should not be generated, but such a large noise signal is detected. This is because, due to the movement of the charging plate 7, induction charging occurs in the copper plates 3 and 4 serving as floating conductors, and a gap of 0.05 mm is generated due to a potential difference caused by the difference in size (dimension, capacitance) between the two. It means that dielectric breakdown occurred and spark discharge occurred. Since the spark discharge is completed at a very high speed in a short time, a broadband transient electromagnetic field (electromagnetic noise) including a frequency component of several GHz or more is emitted. The coaxial noise of the differential probe is received by the electromagnetic noise, and the common mode signal is converted into the normal mode and analyzed by an oscilloscope to obtain the waveform of FIG. Although not particularly shown here, the Teflon (registered trademark) charging plate 7 is negatively charged, and the charging plate 7 such as acrylic has a property of being easily positively charged.

  If electromagnetic noise due to discharge as shown in FIG. 2 is generated inside an electronic device, a malfunction may occur sufficiently in a recent IC. That is, as the insights of the present inventors, when a varying electric field is applied from the outside to an electronic device protected by an insulating case, induction charging occurs inside the electronic device and discharge (induction ESD) occurs. It was found that the electronic device malfunctioned.

  Therefore, when this induced ESD is detected, transient electromagnetic noise (hereinafter referred to as “induced ESD noise”) that is emitted when the induced ESD occurs inside the electronic device may be monitored. However, actually, other electromagnetic noise is frequently generated from the inside of the electronic device or the peripheral device, and this may be erroneously detected. Main sources of noise generated from inside and outside of electronic devices are power switches, electromagnetic switches, relays, motors (especially brush type), electromagnetic solenoids / plungers, power semiconductor devices, inverter circuits, fluorescent lamps, bimetals There are ignition thermostats, high voltage power supply surroundings (example: flyback transformer), dry copy machines, power phase advance capacitor banks, gas appliances and other ignition devices. From these, pulse noise with a large peak and burst noise that repeats quickly are emitted irregularly. Therefore, in a normal noise detection circuit, it is difficult to identify the target induced ESD noise (transient electromagnetic field noise) or other noise. In particular, the time variation of the noise waveform caused by the discharge at the relay contact resembles an electrostatic discharge (ESD) pulse, and thus may be erroneously recognized. It is only necessary to recognize and exclude the electromagnetic spectrum (specific frequency) specific to the noise source, but the noise generation form and propagation path (space / conductor) are quite different, and these should be excluded reliably. It is also difficult. As a result, discrimination from the intended induced ESD noise is extremely difficult.

  Therefore, the present inventors have further conducted analysis on induced ESD. As a result, it has been clarified that the induced ESD has the following characteristics.

  (1) Although there are some differences depending on the discharge gap between the floating conductors corresponding to the gap between the two large and small copper plates 3 and 4, the induced ESD that occurs is spark discharge and is extremely fast. Note that the wider the discharge interval, the greater the voltage applied between the floating conductors to cause induced ESD. That is, in the verification, the magnitude of the applied voltage is linked to the discharge interval. It is also known that the rise time of the induced ESD becomes faster as the applied voltage is smaller, that is, the discharge interval is smaller. FIG. 3 shows the relationship between the applied voltage in the verification and the rise time of the induced ESD.

  (2) The frequency spectrum of the transient electromagnetic field emitted to the periphery by the induced ESD is continuous and extremely wide. FIG. 4 compares the frequency spectrum envelope of the transient electromagnetic field with discrete electromagnetic waves (EMI) radiated as the electronic circuit operates. An electromagnetic wave or the like by an electronic circuit has a spectrum (frequency component) limited to a specific frequency. On the other hand, it can be seen that the transient electromagnetic field generated by the induced ESD is not discrete but has a continuous spectrum over an ultra-wide band. According to the verification by the present inventors, when the discharge interval width is several tens of μm or less, the (frequency) spectrum of the induced ESD noise emitted in the meantime is continuous from near DC to the SHF band (several tens GHz). The distributed ultra-wideband characteristics are shown. This can be said to be close to the characteristics of the delta function in the frequency domain, but the amplitude (power: dBm value) of each (line) spectrum is not so large. This is because the emitted electromagnetic wave energy is dispersed over the entire band. On the other hand, using this characteristic, it is possible to determine the induced ESD noise by taking a very wide band of the receiving circuit. On the other hand, as shown in FIG. 4, the normal noise mixed in each part of the envelope of the spectrum distribution of the induced ESD noise does not show such a broadband property, and the spectrum is concentrated in a narrow band. For example, in the case of power system noise (for example, high frequency noise generated from an inverter), odd harmonics are distributed up to a certain high frequency range, but the upper limit is still several hundred kHz. In general noise sources, the noise occupation band tends to become narrower as the emitted power increases. Therefore, it is considered that only the induced ESD can be detected with high accuracy by utilizing the (super) wideband characteristics of the induced ESD.

  (3) The external electric field corresponding to the plastic charging plate 7, the potential fluctuation of one levitation conductor charged by this external electric field, and the positive and negative charges of the other three levitation conductors receiving the discharge from one levitation conductor Depending on the state, the polarity of the electric field fluctuation occurring in the vicinity thereof is determined. As a result, the polarity (positive slope or negative slope) of the top of the waveform received by the antenna is naturally determined in the vicinity of each of them.

  (4) Normally, the discharge gap between the floating conductors is fixed. Therefore, when the external charging environment due to electrostatic induction continues, even after the discharge is completed, a discharge due to recharging occurs, and a plurality of discharges occur repeatedly (this is often the case). This will be called “multiple discharge”). FIG. 5 shows an example of detecting multiple discharges. The discharge interval is about 10 ms (5 to 15 ms in the example of FIG. 5 and is affected by the moving speed of the charging plate), and it can be seen that six discharges occur within 100 ms. Therefore, a situation in which multiple discharges occur within a predetermined time interval is also an important matter for determining the induced ESD. In general discharge events other than induced ESD, it is impossible to repeatedly discharge in the same place in a short time.

  Therefore, by recognizing the characteristics of the induced ESD considered as described above, the detection technique described later detects only the induced ESD with higher accuracy while distinguishing the induced ESD from other discharge events.

  Next, an electrostatic discharge detection device G1 according to an embodiment of the present invention will be described with reference to FIG. Since the embodiment of the present invention may have many embodiments other than the configurations of FIGS. 6 and 7, the embodiment can be simplified or changed without departing from the flow of basic functions, waveform processing, and the like. , You can add.

  The electrostatic discharge detection device G1 includes an antenna G5, a waveform analysis unit G8, and a discharge determination unit G80. The waveform analysis unit G8 includes first to third frequency analysis units G10 to G30, a polarity analysis unit G40, and a repeated waveform analysis unit G60. The discharge determination unit G80 includes a broadband characteristic determination unit G82, a continuity determination unit G84, a polarity determination unit G86, and an overall determination unit G88.

  Four antennas G5 are provided and connected to the waveform analysis unit G8. One antenna G5-4 is a so-called short monopole antenna, and among the waveform analysis unit G8, a polarity analysis unit G40 (discussed later) for discriminating the polarity of an impulse noise waveform generated by induced ESD, and its discrimination It is used for the repetitive waveform analysis unit G60 using the result.

  The remaining three antennas G5-1, G5-2, and G5-3 are connected to the first frequency analysis unit G10, the second frequency analysis unit G20, and the third frequency analysis unit G30, respectively. Specifically, the antenna G5-1 is connected to the first frequency band filter G12 of the first frequency analysis unit G10. The antenna G5-2 is connected to the second frequency band filter G22 of the second frequency analysis unit G20. The antenna G5-3 is connected to the third frequency band filter G32 of the third frequency analysis unit G30.

  The following first to third frequency components F1 to F3 mean waveform components that pass through the first to third band filters G12, G22, and G32. That is, each of the first to third band filters G12, G22, and G32 has a center frequency and a pass bandwidth based on the center frequency (here, a bandwidth up to 6 dB attenuation). The first to third center frequencies are preferably bands with low radio transmission power and low usage frequency, but can be appropriately changed according to the electromagnetic environment.

In the present embodiment, the following numerical values are set.
First frequency component F1 = first center frequency 1.82 MHz First pass bandwidth 0.1 MHz (−6 dB)
Second frequency component F2 = second center frequency 30.0 MHz Second pass bandwidth 1 MHz (−6 dB)
Third frequency component F3 = third center frequency 200.0 MHz Third pass bandwidth 10 MHz (−6 dB)

  The second frequency component F3 is currently set to the VHF band, but may be changed to the UHF band (300 MHz to 3 GHz) depending on the situation. Although the circuit becomes complicated, the UHF band may be added as a new fourth frequency component F4. A circuit configuration is also possible in which a first frequency band filter to a fourth frequency band filter are prepared in advance and can be appropriately selected during operation.

  The antenna G5-1 for the first frequency analysis unit G10 is a loop antenna (with a slit). This is because the magnetic field component can be downsized in the 1.82 MHz band (MF band). As the antennas G5-2 and G5-3 for the second and third frequency analysis units G20 and G30, small short monopole antennas are used. At any frequency, the source (where the induced ESD is generated) is located very close to the antenna (several centimeters to several tens of centimeters), and is a high gain amplifier such as ordinary radio wave reception. Is not necessary, but a minimum gain (approximately 10 dB to 20 dB) for driving peripheral circuits is necessary.

  Incidentally, for example, a radio wave assumed by a receiving antenna for television is a weak electromagnetic wave (electric field intensity E: several hundred nV / m to several hundred μV / m) coming from a distance and has a specific frequency (f). Is. Moreover, an electromagnetic wave (TEM mode) is assumed in which both the electric field and the magnetic field have only orthogonal components (no component in the traveling direction). Therefore, a normal antenna is designed to efficiently receive radio waves of this specific frequency. For example, when an electric field is received by a television receiving antenna, the two elements are tuned to a specific frequency by matching the half (λ / 2) of the wavelength (λ) of the radio wave to be received. This method increases the antenna sensitivity (gain). Furthermore, in order to amplify the weak antenna output (μV order), a tuned amplifier circuit with a high gain (60 dB or more) and a narrow band is required on the circuit side.

  However, the transient electromagnetic wave generated in the vicinity of the antenna due to the induced ESD is a non-TEM mode in which an electric field or a magnetic field has a traveling direction component and has an impulse waveform that rises very quickly. Furthermore, the frequency component also extends over a very wide band (kHz to GHz). As a result, normal antenna theory cannot be applied straight.

  Therefore, according to the verification by the present inventors, it is found that an antenna that receives a transient electromagnetic wave of induced ESD may be a single element, and it is sufficient from an experiment or the like to have a length of about 5 mm to 20 mm. . This antenna is called a monopole antenna because it is shorter than a normal dipole antenna and has only one element. In particular, in this embodiment, it is called a short monopole antenna because of its short length. The structure is simple and the cost is extremely advantageous. As the element becomes shorter, omnidirectionality becomes stronger, which is particularly preferable when receiving induced ESD with an indefinite radio wave arrival angle.

  In the case of induction ESD, the distance between the wave source and the antenna is about several centimeters to several tens of centimeters, and the antenna induced voltage (impulse shape) is from a peak value of several tens mV even when the antenna length is 5 mm. There are several hundred mV. As a result, the receiving circuit does not require a large gain. However, a certain amount of bandwidth is required to determine the pulse polarity.

  FIG. 8 shows antenna-induced waveforms in a vicinity of two types of induction ESD sources (600 V and 720 V) about 3 cm for verification using a short monopole antenna having a length of 5 mm. 8A and 8B show induced voltage waveforms when induced ESD (720 V) is detected by a short monopole antenna having a length of 5 mm. The distance between the induced ESD generation source and the antenna is about 3 cm, and induced ESD is generated by bringing the charged body of the Teflon sheet closer to the wave source. 8A shows the display at V: 50 mV / div and H: 10 ns / div, and FIG. 8B shows the display at V: 100 mV / div and H: 2 ns / div. Both are examples of positive detection wavemeters.

  FIGS. 8C and 8D show induced voltage waveforms when induced ESD (600 V) is detected by a short monopole antenna having a length of 5 mm. The distance between the induced ESD generation source and the antenna is about 3 cm, and induced ESD is generated by bringing the charged body of the Teflon sheet closer to the wave source. FIG. 8C shows V: 100 mV / div, H: 5 ns / div, and FIG. 8B shows V: 100 mV / div, H: 2 ns / div. Both are examples of positive detection wavemeters.

  FIG. 9 shows an example in which the frequency characteristic of a short monopole antenna having a length of 5 mm is measured with a GTEM cell. The measurement frequency is 50 MHz to 3 GHz, the horizontal axis is frequency (MHz), and the vertical axis is relative sensitivity (dB). Although this measurement is flat (+, -3 dB) up to 3 GHz, flat data is obtained even if it exceeds 8 GHz in another measurement (not shown), indicating that the short monopole antenna has ultra-wideband characteristics. The pulse rise time (tr) of an impulse electromagnetic wave due to induced ESD is on the order of several tens of ps. When the pulse transmission (delay) time (tpd) in the antenna element approaches the pulse rise time (tr), the antenna The received waveform becomes oscillating. For example, when the pulse rise time tr of the electromagnetic wave is 50 ps, it is known that the received waveform vibrates when the element becomes longer than 30 mm.

  Therefore, the length of the monopole antenna is desirably 100 mm or less, particularly 30 mm or less, and more preferably 5 mm to 20 mm. The size of the ground plane of the antenna may be appropriately selected depending on the installation environment.

  Returning to FIG. 6, the waveform analysis unit G8 to which the antenna G5 is connected includes a first frequency analysis unit G10, a second frequency analysis unit G20, a third frequency analysis unit G30, a polarity analysis unit G40, and a repetitive waveform. An analysis unit G60 is provided.

  The first frequency analysis unit G10 determines whether or not at least the first frequency component F1 is included in the detection signal of the antenna G5-1. The second frequency analysis unit G20 determines whether or not at least the second frequency component F2 is included in the detection signal of the antenna G5-1. The third frequency analysis unit G30 determines whether or not at least the third frequency component F3 is included in the detection signal of the antenna G5-3. Since the detailed configurations of the first to third frequency analysis units G10, G20, and G30 are almost the same, the first frequency analysis unit G10 will be described in detail here, and the second and second frequency analysis units G20, Description of G30 is omitted.

  The first frequency analysis unit G10 includes a first frequency band filter G12, an RF amplifier G14, a detection circuit G16, an output homogenization circuit G17, and a latch circuit G18.

  The first frequency band filter G12 is a band pass filter that passes the first frequency component F1 as a signal that matches the first center frequency and the first pass bandwidth. The insertion loss in the pass band of the first frequency band filter G12 is preferably 12 dB or less. The first band filter G12 is preferably housed in a shield case to prevent coupling with other circuits or transient electromagnetic fields due to induction ESD.

  It should be noted that the durations of the signals exiting the first to third frequency band filters G12, G22, G32 become shorter in inverse proportion to the pass bandwidth. For example, the first frequency band filter G12 has 10 μs, the second frequency band filter G22 has 1 μs, and the third frequency band filter G32 has 0.1 μs.

  In addition, although the 1st-3rd center frequency in this embodiment is set as mentioned above, it is preferable to set to a band with little radio | wireless transmission power especially and low use frequency. Moreover, it is not necessarily limited to these frequencies, You may change suitably according to electromagnetic environment.

  In particular, the first to third frequency components F1 to F3 are 0.3 to 3 MHz band that is an MF (medium wave) band, 3 to 30 MHz band that is an HF (short wave) band, and 30 to 30 that are VHF (very short wave) bands. It is preferable to make it a condition that it belongs to at least two bands from the 300 MHz band to 300 GHz band and the 300 MHz to 3 GHz band which is a UHF (ultra-high frequency) band. Therefore, it is desirable to determine the first to third center frequencies from at least two or more bands in the band, and it is more preferable to determine from the three bands. More desirably, a total of four types of center frequencies are determined from each band. In the present embodiment, the first center frequency is extracted from the MF band, the second center frequency is extracted from the HF band, and the third center frequency is extracted from the VHF band.

  In the present embodiment, the second frequency component F3 belongs to the VHF band, but it may be changed to the UHF band depending on the situation. Also, as already described, the UHF band can be added as a new fourth frequency component F4. Convenience can also be improved by preparing the first frequency band filter F1 to the fourth frequency band filter F4 in advance and adopting a circuit configuration that can be appropriately selected during operation.

  The RF amplifier G14 amplifies the signal output from the first frequency band filter G12. For example, when the signal level output from the first frequency band filter G12 is on the order of several tens of mV, the next-stage detection circuit G16 cannot be directly driven as it is, and thus it is necessary to amplify. Furthermore, since the duration of the output signals of the first to third frequency band filters G12, G22, G32 is shortened in inverse proportion to the passband width, this RF amplifier G14 also requires a certain band. Therefore, it is preferable that the gain of the RF amplifier G14 is 10 times (20 dB) and the bandwidth is 100 kHz to 500 MHz. The output levels of the RF amplifiers G14, G24, G34 of the first to third frequency analysis units G10, G20, G30 are set to the same level as much as possible. This is for efficiently operating the detection circuits G16, G26, G36 in the next stage.

  The detection circuit G16 envelope-detects the vibration signal output from the RF amplifier G14. As a result, a pulse-like signal having an output time width (vibration duration) of the first frequency band filter G12 can be extracted.

  The output homogenization circuit G17 homogenizes the waveforms of the pulse signals output from the detection circuits G16, G26, G36 of the first to third frequency analysis units G10, G20, G30. Note that the pulse widths of the pulse signals output from the detection circuits G16, G26, G36 are different. In addition, skew due to a difference in threshold value of the diode in each detection circuit may occur. Therefore, even if the pulse signals output from the detection circuits G16, G26, and G36 are input to the latch circuit as they are, accurate determination cannot be performed in the subsequent discharge determination unit G80. Therefore, it is converted into a fixed pulse width and a fixed pulse amplitude that are common to each other without depending on the pulse width of the pulse signals output from the detection circuits G16, G26, and G36. Specifically, a monostable multivibrator is used in this embodiment.

  The latch circuit G18 latches the homogenization signal output from the output homogenization circuit G17, and outputs the signal to the discharge determination unit G80.

  With the above configuration, the first frequency analysis unit G10 analyzes whether or not the detection signal of the antenna G5-1 includes the first frequency F1. When the first frequency is included in the detection signal, a latch output from the latch circuit G18 is obtained. The same applies to the second and third frequency analysis units G20 and G30.

  The discharge determination unit G80 includes a broadband characteristic determination unit (AND circuit) G82, and latch outputs of the first to third frequency analysis units G10, G20, and G30 are introduced. When the AND circuit G82 is ON (HI), the detection signal obtained from the antenna G5 includes the first, second, and third frequency components F1, F2, and F3 in substantially the same output waveform. Will be. As a result, it is determined that a transient electromagnetic field based on the induced ESD has occurred.

  As shown in FIG. 7, the polarity analyzer G40 includes a wideband amplifier G44, a positive polarity amplifier G46, a negative polarity amplifier G48, a positive level comparator G50, and a negative level connected to the antenna G5-4. A comparator G52 and a frequency discriminator G54 are included.

  The antenna G5-4 uses a short monopole antenna as described above. A loop antenna (with a slit) can also be used. When the output of the antenna G5-4 does not reach several hundred mV, the wideband amplifier G44 amplifies a wideband having a gain of 20 dB and a bandwidth of about 10 kHz to 3 GHz. Note that, when the gain of the antenna G5-4 is sufficient, the broadband amplifier G44 is unnecessary.

  The plus polarity amplifier G46 and the minus polarity amplifier G48 further amplify the waveform output from the wideband amplifier G44 for each plus polarity and minus polarity to a level that can be compared by a level comparator in the subsequent stage. However, the positive polarity and the negative polarity do not necessarily have to be amplified using separate amplifiers. The output amplified by one amplifier may be connected to the + side level comparator G50 and the minus side level comparator G52. The positive polarity waveform has already been shown in FIG. Although not shown in particular, the negative polarity waveform has a polarity opposite to these (a state in which the leading portion swings to the negative side). Further, depending on the characteristics of the antenna G5-4, there may be a damped oscillation waveform in a burst state instead of a single impulse as shown in FIG.

  The plus side level comparator G50 compares whether or not the signal amplitude amplified by the plus polarity amplifier G46 exceeds the plus side comparison voltage at the set level. Similarly, the minus side level comparator G52 compares whether or not the signal amplitude amplified by the minus polarity amplifier G47 exceeds the minus side comparison voltage at the set level. The absolute values of the + side comparison voltage and the minus side comparison voltage are the same.

  The signal previously output from either the plus side level comparator G50 or the minus side level comparator G52 passes through the inverting AND gate, and the clock of the plus side latch circuit G53 or the minus side latch circuit G54 ( CLK) terminal. The plus side latch circuit G53 or the minus side latch circuit G54 is a so-called D-type flip-flop.

For example, when a signal is output first from the plus side level comparator G50, the signal is input to the clock terminal, the plus side latch circuit G53 is triggered, and the Q output is turned ON (HI). _{The X} output is turned off (LO). The Q output is input to a plus-side single waveform generation circuit G55 described later.

Q _X output of the plus-side latch circuit G53 is input to the inverting AND gate having a negative polarity side. As a result, while the plus side latch circuit G53 is being triggered, the output from the minus side level comparator G52 cannot pass through the inversion AND gate on the minus polarity side, so that the trigger of the minus side latch circuit G54 is prohibited. The Note that the trigger of the plus-side latch circuit G53 is reset, Q _X output ON (HI), and the output from the minus side level comparator G52, through the inverting AND gate having a negative polarity side, a negative The side latch circuit G54 can be triggered.

For example, when a signal is output first from the negative side level comparator G52, the signal is input to the clock terminal, the negative side latch circuit G54 is triggered, and the Q output is turned ON (HI). Q _X output is OFF (LO). The Q output is input to a minus side single waveform generation circuit G56 described later.

Q _X output of the negative-side latch circuit G54 is input to the inverting AND gate having a positive polarity side. As a result, while the minus side latch circuit G54 is being triggered, the output from the plus side level comparator G50 cannot pass through the inversion AND gate on the plus polarity side, so that the trigger of the plus side latch circuit G53 is prohibited. The Note that the trigger of the negative-side latch circuit G54 is reset, its Q _X output ON (HI), and the output from the positive side level comparator G50, through the inverting AND gate having a positive polarity side, The positive side latch circuit G53 can be triggered.

  In this way, by arranging two inversion AND gates between the plus and minus level comparators G50 and G52 and the plus and minus latch circuits G53 and G54, the plus and minus sides are arranged. It can be prohibited that the latch circuits G53 and G54 are triggered simultaneously. As a result, the transition of the positive / negative polarity of one repetitive waveform can be analyzed accurately.

  The positive side and negative side single waveform generation circuits G55 and G56 to which the respective Q outputs of the positive side and negative side latch circuits G53 and G54 are input are so-called monostable multivibrators. A wide single pulse having a width (here, set to 1 ms) is output. This wide single pulse is input to each polarity of the subsequent repeated waveform analysis unit G60.

  The wide single pulse output from one of the plus-side and minus-side single waveform generation circuits G55 and G56 passes through the first OR gate for initialization and is set to a narrow pulse width (here, 1 μs). The single waveform generator for reset G57 (also a monostable multivibrator) is triggered, whereby a single pulse for reset is output from the single waveform generator for reset G57. This narrow single pulse is input to the CLR terminals of the plus side and minus side latch circuits G53 and G54 via the initialization second OR gate to reset these triggers. As a result, the plus-side and minus-side latch circuits G53 and G54 are in a state of waiting for signals previously output from the plus-side and minus-side level comparators G50 and G52.

  An initialization signal is also input to the second OR gate for initialization. This initialization signal is input when initialization at the time of system startup is performed or when waiting for the next series of discharge events after the end of the series of discharge detection.

Also, D-type flip-flop of the plus side and minus-side latch circuit G53, G54 from the clock (CLK) input, it is preferable that the propagation delay time from Q and Q _X output to use one as soon as possible. The repetition period of the vibration of the damped vibration type detection signal obtained from the induced ESD is as high as several ns, although it depends on the detection antenna used. Therefore, it is preferable to use a high-speed flip-flop in order to make a circuit in which the other AND gate can be prohibited within one cycle after a signal is input to one D-type flip-flop. In the present embodiment, an example of a D-type flip-flop is shown, but other types of flip-flops can be used.

  Returning to FIG. 6, the wide single pulses respectively output from the plus-side and minus-side single waveform generation circuits G55 and G56 of the polarity analysis unit G40 are input to the repeated waveform analysis unit G60. The repeated waveform analysis unit G60 determines whether or not the detection signal of the antenna G5-4 includes a plurality of output waveforms. In the present embodiment, the repetitive waveform analysis unit G60 is provided at the subsequent stage of the polarity analysis unit G40, so that the number of outputs is counted for each plus waveform and every minus waveform. On the other hand, the present invention is not limited to this, and the number of outputs may be counted without distinguishing only a plus waveform, only a minus waveform, or a plus waveform and a minus waveform.

  The repetitive waveform analysis unit G60 includes a timer AND gate, a plus counter G64, a minus counter G68, and a measurement timer G69. The wide single pulses on the positive electrode side and the negative electrode side of the polarity analyzer G40 are input to the plus side counter G64 and the minus side counter G68, respectively, via the timer AND gate. Note that the measurement gate signal output from the measurement timer G69 is input to the timer AND gate. The first wide single pulse output from the plus side or minus side single waveform generation circuits G55, G56 triggers the measurement timer G69 via the OR gate. As a result, the measurement timer G69 outputs a measurement gate signal for a predetermined time. The measurement gate signal sets an observation time for observing a series of discharge events, and can be freely set to, for example, 1 second or 10 seconds.

  The plus side counter G64 counts the wide single pulse on the positive side and determines whether or not the count exceeds a predetermined threshold (2 to 10 times). Similarly, the minus side counter G68 counts the wide single pulse on the negative side, and determines whether or not the count exceeds a predetermined threshold (2 to 10 times). Each determination result, count number, and interval (vibration cycle) between counts are output to the discharge determination unit G80.

  The discharge determination unit G80 includes a repeatability determination unit (OR circuit) G84 and a polarity determination unit G86 separately from the broadband characteristic determination unit (AND circuit) G82 already described. The repeatability determination unit G84 determines that there is a repeat characteristic when one of the plus side counter G64 and the minus side counter G68 exceeds a predetermined threshold. Although not specifically described here, the count value of the plus-side counter G64 or minus-side counter G68 needs to be counted within the reference time. This corresponds to the pulse width of the measurement gate signal by the measurement timer G69 of G60. Since the transient electromagnetic field of the induced ESD often has repetitive generation characteristics, the determination result of the repeatability determining unit G84 can be used as a determination of the presence or absence of induced ESD.

  Furthermore, the discharge determination part G80 is provided with the comprehensive determination part G88. The overall determination unit G86 makes a final determination as to whether or not the induced ESD has occurred using the determination results of both the broadband characteristic determination unit G82 and the repeatability determination unit G84. In the present embodiment, an AND circuit is employed as the comprehensive determination unit G88, and only when it is determined that both the wideband characteristic determination unit G82 and the repeatability determination unit G84 have the wideband characteristic and the repeat occurrence characteristic. Thus, it is determined that the induced ESD has occurred. Thereby, the accuracy of the determination is improved. If it is desired to allow some errors and determine the possibility of occurrence of induced ESD widely, an OR circuit is used in the overall determination unit G88. As a result, when one of the broadband characteristics by the broadband characteristics determination unit G82 and the repeat generation characteristics by the repeatability determination unit G84 is present, it can be determined that induced ESD has occurred.

  As described above, according to the electrostatic discharge detection device G1 of the present embodiment, the waveform characteristics of the transient electromagnetic field received by the antenna G5 are analyzed, and whether the transient electromagnetic field has a broadband characteristic or a repeated generation characteristic. It is possible to determine and use the result to detect the occurrence state of the induced ESD. In particular, when the presence of a transient electromagnetic field having a bandwidth of 30 MHz or more, particularly a bandwidth of 100 MHz or more, which is peculiar to a transient electromagnetic field of induced ESD, it can be determined that induced ESD has occurred.

  In the electrostatic discharge detection device G1 of the present embodiment, the broadband characteristics of the transient electromagnetic field are analyzed depending on whether or not a plurality of frequency components are simultaneously generated in the transient electromagnetic field. Here, the broadband characteristics of the transient electromagnetic field are analyzed using the presence / absence of the occurrence of the first to third frequency components F1 to F3 at three locations. In addition, as the first to third frequency components F1 to F3, two separate bands selected from the MF (medium wave) band, the HF (short wave) band, the VHF (ultra high frequency) band, and the UHF (ultra high frequency) band ( Since the first to third frequency components F1 to F3 belong to preferably three bands), the wideband characteristics can be analyzed more reliably. The setting of the first to third frequencies is not limited to the above setting method. For example, in order to detect a wideband characteristic having a bandwidth of about 30 MHz or more, the difference between the maximum value and the minimum value of the plurality of set frequencies. Is also preferably set to about 30 MHz or more. Desirably, the difference between the maximum value and the minimum value is set to about 100 MHz or more.

  Further, in the present embodiment, the waveform analysis unit G8 includes a repeated waveform analysis unit G60, and analyzes whether or not a plurality of transient electromagnetic field waveforms are generated in a short time. As a result, it is possible to reliably analyze whether or not it has a repeated generation characteristic that is a characteristic of the transient electromagnetic field of the induced ESD. As a result, the discharge determination unit G80 can detect the induced ESD with higher accuracy. In particular, in the present embodiment, the polarity analysis unit G40 distinguishes between positive and negative of each impulse waveform, so that it is possible to determine what kind of electrostatic induction has caused the induced ESD.

  In this electrostatic discharge detection device G1, an amplifier is not installed immediately after the antennas G5-1, G5-2, and G5-3. However, an amplifier may be arranged when the output is insufficient. Moreover, although the case where antenna G5-1, G5-2, G5-3 was provided independently in 1st-3rd frequency analysis part G10, G20, G30 was illustrated, this invention is not limited to this, One The antenna output may be distributed to the first to third frequency analysis units G10, G20, and G30.

  Here, the case where both the frequency analysis units G10 to G30 and the repeated waveform analysis unit G60 are provided in the waveform analysis unit G8 is illustrated, but the present invention is not limited to this. For example, the presence / absence of induced ESD can be determined using the analysis results of the frequency analysis units G10 to G30 and the determination result of the broadband characteristic determination unit G82. Conversely, it is also possible to determine the presence or absence of induced ESD using the analysis result of the repetitive waveform analysis unit G60 and the determination result of the repeatability determination unit G84.

  Next, the fluctuation electric field tolerance inspection apparatus according to the embodiment of the present invention will be described. This Fluctuating Electric Field Tolerance Inspection Device is a rapid discharge (spark discharge) between levitation conductors by forcibly inductively charging the levitation conductor existing inside and around the electronic device to be inspected and the electronic device. ) And the induced ESD is detected by the already described electrostatic discharge detection device G1, and the presence or absence of malfunction due to the discharge is inspected.

  For example, the main trouble that the variable electric field resistance inspection device is inspecting is that there is no direct ESD to the electronic device or indirect ESD around the device, but the electronic device malfunctions. It is a phenomenon that causes it. That is, a phenomenon in which an operator of an electronic device or a charged object in the vicinity does not contact the electronic device to be inspected (no discharge has occurred with respect to the electronic device) and causes a malfunction. Electrostatic discharge that induces malfunctions occurs inside electronic equipment and occurs in a narrow gap between adjacent metal conductors, so the frequency components contained in the emitted transient electromagnetic waves are extremely wide (several GHz or more). ) And very strong, and the electric field strength easily reaches the order of kV / m. As a result, an LSI (for example, a CPU or IC) or the like that is arranged near the discharge source or connected via a signal line passing through the vicinity of the discharge source induces a malfunction. Such troubles can only be detected, evaluated, and addressed by the method using the variable electric field resistance inspection apparatus according to the present invention.

  In general, when a CPU IC or the like malfunctions, it is common that the CPU automatically restarts automatically. However, in the case of an electronic device constituting a part of a large-scale network, the computer at the center is interrupted through a communication line. If an interrupt is input from a large number of electronic devices, the processing capacity of the entire system is greatly reduced, and a system failure may occur. In particular, the transient electromagnetic field emitted by this phenomenon is very powerful, so if all of the electronic devices with multiple redundant configurations (eg, double parallel operation) used in the backbone infrastructure are malfunctioned. As a result, a serious accident may be directly connected.

  In avionics and defense equipment, strict defensive measures are taken against electromagnetic interference (EMI) caused by radar waves, but the electric field strength of the electromagnetic wave irradiation test (example: RTCA DO-160E) as the basis is The maximum is 600 V / m (0.4 GHz to 18 GHz). Although this value is comparable to the electric field intensity when irradiated from a 1000 kW (1 MW) pulse radar at a distance of 10 m from the device, the method we propose this time exceeds 1 kV / m inside the device. An electric field strength can be generated, making it possible to test its resistance. Further, according to the present invention, there is no need for an expensive and large anechoic chamber, a high power power amplifier, a radiating antenna or the like. According to the verification by the present inventors, when the discharge gap is about 0.05 mm, the spectrum distribution observed by the spectrum analyzer is well over 18 GHz, and the impulse for driving the floating conductor (small dipole) It has been found that the rise of the current is very fast (estimated less than 40 ps) and has a large amplitude (depending on the amount of charge, on the order of tens of A to 100 A).

  Next, referring to FIG. 10A to FIG. 10D and subsequent drawings, the variation electric field resistance inspection apparatus according to the first embodiment for forcibly inducing the special discharge phenomenon in the electronic apparatus and inspecting the resistance of the electronic apparatus. (Hereinafter, inspection apparatus) 10 will be described. 10A is a front view of the inspection apparatus, FIG. 10B is a top view of the inspection apparatus, FIG. 10C is a side view of the inspection apparatus, and FIG. 10D is a control panel of the main body of the inspection apparatus.

  The inspection apparatus 10 includes a main body 15, an application electrode 20, an electric field variation unit 30, a housing 40, the electrostatic discharge detection device G 1 (FIGS. 6 and 7) of the above embodiment, a synchronization control unit 60, and a mounting table 70. ing. An electric field fluctuation unit 30, an electrostatic discharge detection device G 1, and a synchronization control unit 60 are accommodated in the housing 40 of the main body 15.

  The application electrode 20 applies one positive or negative electric field from the outside to the electronic device P to be measured in a non-contact state. The application electrode 20 has a so-called plate shape (plate shape), and this plane is a field emission surface 22. The application electrode 20 is fixed in a standing state on the mounting table 70 so that the field emission surface 22 faces the side surface of the electronic device P.

  The mounting table 70 is horizontally disposed so as to protrude from the side surface of the main body 15, and at least the upper surface is formed of an insulator. An electronic device P is disposed in the center of the mounting table 70.

  Here, the electric field variation means 30 is a voltage control device and is accommodated in the housing 40. The electric field variation means 30 varies the strength of the electric field generated from the application electrode 20 without changing the polarity by changing the DC voltage applied to the application electrode 20. Thereby, the strength of the electric field applied to the electronic device P during the inspection can be changed over time without changing the polarity. If a floating conductor (a conductor that is not grounded) exists inside the electronic device P, when the electric field applied to the electronic device P is varied, induction charging occurs in the floating conductor. In the inspection apparatus 10, whether or not there is a structure that generates a spark discharge in and around the electronic device P by forcibly generating this inductive charge in the electronic device P, and thereby the electronic device P malfunctions. The operational characteristics such as whether or not to perform can be verified. Specifically, when the other conductor is arranged close to the floating conductor inside the electronic device P, a discharge phenomenon may occur between the two as shown in the verification example. By providing an environment in which this discharge is forcibly generated, the presence or absence of the discharge is verified, and at the same time, the resistance to noise is inspected.

  A control panel 42 (see FIG. 10D) is prepared in the housing 40 of the main body 15. The control panel 42 includes a radiation voltage setting unit (Test Voltage), a test start button (Start), a test end button (Stop), and a repeat setting unit (sets the number of tests (voltage application count)) in the range of 0 to 9 times ( Repetition), application time setting unit (Timing) for setting the application timing (delay timing) of the voltage supplied to each electrode in the case of multiple electrodes specification within a range of 0.1 to 1 second, and the application slope of the same voltage is 0 .Slope setting section (Ramp) set within the range of 1 to 1 second, connector section (Output) for connecting wiring for supplying voltage to each electrode, polarity setting section (Polarity) for switching the polarity of the high voltage electric field, electronic equipment Terminal for supplying ground potential to the inspection head jig (FG), connector for detecting discharge probe (Disc. Probe), connector for detecting charged potential probe (V Probe), multi-axis movement to move the applied electrode B Tsu bets and a like connector for controlling (described in the second embodiment) (Control).

  The radiation voltage setting unit (Test Voltage) sets the applied voltage within a range of 0 to −25 kV or 0 to +25 kV.

  The inspection start button (Start) and the inspection end button (Stop) are buttons for manually starting and ending the test. When the number of times set in the repeat setting section (Repetition) is set to 0, the test is repeatedly performed from when the test start button (Start) is pressed until the test end button (Stop) is pressed. On the other hand, if the number of tests (the number of times of voltage application) is set in the range of 1 to 9, the test is automatically terminated when the test collection is completed.

  The discharge detection antenna of the electrostatic discharge detection device G1 is connected to the connection connector (Disc. Probe) of the discharge detection probe. This antenna receives and amplifies and detects electromagnetic waves emitted by discharge, and notifies the user by an alarm sound or LED display. A function of transmitting this detection signal to the main body 15 and recording it as a history may be incorporated. Further, a charging detection antenna (not shown) is connected to the connection connector (V Probe) of the charging potential detection probe. The electrification detection antenna detects electric field fluctuations, further amplifies and then performs signal processing to detect electrification. Note that these discharge detection and charged potential detection functions can be incorporated in the main body 15.

  FIG. 11A schematically shows the time fluctuation of the electric field emitted from the application electrode 30 by the electric field changing means 30, and FIG. 11B schematically shows the time fluctuation of the induction charging acting on the electronic device P. It is shown.

  First, the electric field variation means 30 gradually increases the absolute value of one of the positive and negative DC voltages applied to the application electrode 20, thereby generating an electric field E <b> 1 that becomes an increase region from the application electrode 20. Here, the electric field E1 is set to be positive. As a result, a positive induction charging T1 that gradually increases occurs in the electronic device P. By this operation, discharge and malfunction when the positive first induction charging T1 occurs in the electronic device P are inspected.

  Thereafter, with the electric field E1 of the application electrode 20 maintained, the first induction charging T1 of the electronic device P is grounded to temporarily reset the potential. Further, by reducing the absolute value of the positive or negative voltage applied to the application electrode 20 until it becomes 0 V, an electric field E2 that is a decrease region is generated from the application electrode 20. As a result, a negative second induction charging T2 that is gradually increased and opposite to the first induction charging T1 is generated for the electronic device P. By this operation, discharge and malfunction when negative second induction charging T2 occurs in the electronic device P are inspected.

  In other words, according to the electric field variation means 30, positive and negative induction charging phenomena can be caused to the electronic device P only by supplying one positive or negative voltage to the application electrode 20. Therefore, the device configuration can be simplified.

  Incidentally, in the present embodiment, the electric field variation means 30 can adjust the voltage (radiation voltage) within the range of −25 kV to +25 kV with respect to the application electrode 20, and can generate both positive and negative electric fields. The voltage supply repetition rate can be adjusted in the range of 2 to 10 seconds / time. The slope of the applied electric field can be controlled in 0.1 second to 1 second.

  Although not specifically shown here, the induction charging reset in the electronic device P is connected to a ground terminal (FG) capable of switching the ground state ON / OFF to the electronic device P. It is preferable to forcibly reset the electric field changing means 30 by switching the ground terminal ON / OFF. On the other hand, when the strength (absolute value) of the electric field applied to the electronic device P reaches a certain level (voltage determined by the gap between adjacent conductors and other conditions), the electric device P spontaneously discharges. When the natural discharge is detected, the control may be performed so that the increase in voltage is stopped and the decrease starts. In this way, the ON / OFF switch for the ground terminal can be omitted.

  The synchronization control means 60 synchronizes the sensing timing of the electrostatic discharge detection device G1 (FIGS. 6 and 7) and the electric field fluctuation timing by the electric field fluctuation means 30. This is because in one inspection, it is necessary to repeatedly apply an electric field to the electronic device P to detect the presence or absence of the discharge state. Here, the number of repetitions of electric field application can be selected within a range of 1 to 9, or a pattern to be continuously applied can be selected until forced stop.

  As described above, according to the inspection apparatus 10 of the first embodiment, a situation in which a so-called charged body approaches or leaves the electronic device P from the outside can be created in a pseudo manner. As a result, for example, malfunction of the electronic device P can be inspected based on a phenomenon in which clothes or a human body charged with static electricity approaches or leaves the electronic device P. In particular, according to this inspection apparatus 10, since the electric field intensity generated from the application electrode 20 is increased or decreased, a situation where the charged body approaches or separates virtually is created, so that the apparatus structure is greatly simplified, and Stable inspection is possible.

  Furthermore, according to the inspection apparatus 10, it is possible to verify the discharge phenomenon generated inside the electronic device P due to the fluctuation of the external electrostatic field, not the direct discharge using the conventional ESD gun. Therefore, it is possible to guarantee the operation assuming the movement of the user (static charge holder) who operates the electronic device P, and the reliability and safety of the electronic device P can be further improved.

  In a specific inspection, the number of discharge phenomena occurring inside the electronic device P by the electrostatic discharge detection device G1, the magnitude of the amplitude (noise intensity) when the discharge waveform is detected, the spectrum distribution, the electronic device What is necessary is just to verify the fluctuation | variation electric field tolerance of the electronic device P using suitably information, such as whether P has actually produced malfunction.

  Next, an inspection apparatus 110 according to the second embodiment will be described with reference to FIGS. 12A and 12B. 12A is a side view of the inspection apparatus 110, and FIG. 12B is a top view. Note that the last two digits of the reference numerals used in the illustration and description of the inspection apparatus 110 are the same as the reference numerals of the inspection apparatus 10 of the first embodiment, thereby omitting redundant description. The difference will be mainly described.

  The inspection apparatus 110 includes a moving mechanism 180 that changes the relative distance S between the electronic device P and the application electrode 120 as the electric field control means 130. The intensity of the electric field applied to the electronic device P is changed by the change in the relative distance S.

  Specifically, the moving mechanism 180 includes an X-axis guide 182 disposed in the horizontal direction, a Y-axis guide 184 disposed on the X-axis guide 182, and a Z-axis rotation motor 186 disposed on the Y-axis guide 184. And an arm member 188 held by the Z-axis rotation motor 186. An application electrode 120 is fixed to the tip of the arm member 188. It is also possible to realize a three-axis movement by further adding a Z-axis guide for controlling the movement in the height direction (Z direction).

  The X axis guide 182 conveys the Y axis guide 184 in the X axis direction, and the Y axis guide 184 conveys the Z axis rotation motor 186 in the Y axis direction. The Z axis rotation motor 186 rotates the arm member 188. By the combination of these movements, the application electrode 120 can freely rotate in the XY plane and in the Z axis. The synchronization control means 160 synchronizes the sensing timing of the electrostatic discharge detection device G1 with the movement timing of the movement mechanism 180.

  According to this inspection apparatus 110, it is possible to move the charged body closer to or away from the electronic device P from various directions and angles, thereby changing the electric field applied to the electronic device P. Can do. For example, a situation in which a person wearing easily charged clothes such as chemical fibers passes through an automatic ticket gate can be verified in a pseudo manner. In other words, according to the present inspection apparatus 110, it is possible to simulate various electric field fluctuation patterns to cause inductive charging in the electronic device P and confirm whether or not a malfunction occurs.

  Although the case where the strength of the electric field applied to the electronic device P is changed by the change of the relative distance S by the moving mechanism 180 is shown here, the present invention is not limited to this, for example, in addition to the change of the relative distance S Further, by changing the supply voltage to the application electrode 120 as shown in the first embodiment, it is possible to perform more advanced electric field control. Here, the case where the relative distance S between the electronic device P and the application electrode 120 is changed by moving the application electrode 120 using the movement mechanism 180 is illustrated, but of course, the electronic device P side is moved to the movement mechanism 180. For example, the relative distance S between the electronic device P and the application electrode 120 may be changed. Furthermore, by moving both the electronic device P and the application electrode 120, the relative distance S between them can be changed.

  Next, an inspection apparatus 210 according to the third embodiment will be described with reference to FIGS. 13A and 13B. FIG. 13A is a top view of the inspection apparatus 210, and FIG. 13B is a side view. Note that the last two digits of the reference numerals used in the illustration and description of the inspection apparatus 210 are the same as the reference numerals of the inspection apparatus 10 of the first embodiment, thereby omitting redundant description. The difference will be mainly described.

  In the inspection apparatus 210, first to third application electrodes 220A to 220C are arranged. Specifically, when the electronic device P is assumed to be a hexahedron, the first application electrode 220A is disposed to face the first surface of the hexahedron, and the second application electrode 220B is perpendicular to the first surface of the hexahedron. The third application electrode 220C is arranged to face the third surface that is perpendicular to both the first surface and the second surface of the hexahedron. By doing in this way, the three surfaces in the hexahedron are inspected collectively in one inspection step. Therefore, by reversing the electronic device P, the inspection of all six surfaces can be completed in two inspection steps, so that the inspection efficiency can be improved.

  Furthermore, according to the inspection apparatus 210, the DC voltage applied to the first to third application electrodes 220A to 220C is shifted while shifting the timing (phase), for example, from the first application electrode 220A to the second application electrode. It is possible to verify the electric field fluctuation that moves to the application electrode 220B side. In addition, by verifying the situation where the charged body approaches or leaves the electronic device P simultaneously from a plurality of directions by simultaneously supplying voltages to the first to third application electrodes 220A to 220C. Will also be possible.

  Next, an inspection apparatus 310 according to the fourth embodiment will be described with reference to FIG. 14A is a top view of the inspection apparatus 310, and FIG. 14B is a graph of a voltage control timing waveform in the inspection apparatus 310. Note that the last two digits of the reference numerals used in the illustration and description of the inspection apparatus 310 are the same as the reference numerals of the inspection apparatus 10 of the first embodiment, thereby omitting redundant description. The difference will be mainly described.

  The inspection device 310 is arranged such that all of the first to fifth application electrodes 320A to 320E are opposed to one surface of the electronic device P. Further, these first to fifth application electrodes 320 </ b> A to 320 </ b> E are embedded in one insulator 324. As a result, the field emission surface 322 by the plurality of application electrodes 320 </ b> A to 320 </ b> E is connected to form one common field emission surface 328. In the common field emission surface 328, since the potential can be partially changed, a gradient can be formed in the electric field generated in the space near the electronic device P.

  The insulator 324 has a sheet shape made of nylon or the like, and the first to fifth application electrodes 320A to 320E are preferably made of a flexible high resistance material such as conductive rubber. Accordingly, the first to fifth application electrodes 320A to 320E are insulated from each other.

  The electric field variation means 330 controls the supply voltages for the first to fifth application electrodes 320A to 320E independently of each other. As shown in FIG. 14B, a voltage with a shifted timing is applied to the first to fifth application electrodes 320A to 320E. As a result, the first to fifth application electrodes 320A to 320E can apply electric fields having different timings to the electronic device P. That is, an electric field that moves in the order of the first to fifth application electrodes 320A to 320E along the surface direction of the field emission surface 322 can be applied to the electronic device P. Note that the voltage supply waveforms are preferably overlapped with each other between adjacent application electrodes, and an electric field that moves smoothly can be created.

  For example, when the electronic device P is an automatic ticket gate, the first to fifth application electrodes 320A to 320E are arranged on the side surface of the automatic ticket gate, and a varying electric field is applied. As a result, it becomes possible to artificially create a situation in which a user with static electricity walks and passes through the side of the automatic ticket gate.

  In addition, although the case where the 1st-5th application electrodes 320A-320E are arrange | positioned along a straight line was shown here, as FIG. 15A shows, for example, the 3rd application electrode 320C is the closest to the electronic device P Alternatively, the first and fifth application electrodes 320A and 320E may be arranged in a V shape so that they are farthest from each other. If the voltage is controlled as shown in FIG. 14B in such a state, it is possible to create an environment in which the electric field approaches and moves away from the electronic device P. Conversely, as shown in FIG. 15B, the first to fifth application electrodes 320 </ b> A to 320 </ b> E can be arranged along the V shape or the arc shape so as to surround the electronic device P.

  Moreover, since these 1st-5th application electrodes 320A-320E are covered by the insulator, it is also possible to test | inspect in the state affixed on the electronic device P. FIG. By pasting, the applied electric field can be strengthened even when the voltage is low.

  Furthermore, here, the first to fifth application electrodes 320 </ b> A to 320 </ b> E are plate-shaped (plate-shaped), and these planes serve as the field emission surface 322, and are illustrated as facing the electronic device P. However, for example, as illustrated in FIG. 15C, it is also preferable that the end surfaces of the first to fifth application electrodes 320 </ b> A to 320 </ b> E serve as field emission surfaces 322 and are arranged so that the end surfaces face the electronic device P. The plurality of field emission surfaces 322 are connected to form one common field emission surface 328. Since the density of the lines of electric force is increased on the end face of the plate as compared with the plane of the plate serving as the electrode, it is possible to efficiently induce induction charging for the electronic device P. Although not shown here, it is also preferable to round the corners of the periphery of the plate forming the first to fifth application electrodes 320A to 320E. This is because when the corners are sharp, corona discharge is likely to occur therefrom. There are several problems caused by corona discharge. One is that the potential of the applied electrode is lowered by corona discharge, thereby reducing the field emission performance. Next, ozone is released by discharge, and the surroundings are corroded and oxidized. Furthermore, discharge noise is emitted by corona discharge. The discharge noise due to corona discharge is characterized in that the frequency spectrum including the radiation noise is extremely narrow and the noise level is low as compared with the spark discharge generated by the induced ESD to be detected by this apparatus.

  Furthermore, although the case where the first to fifth application electrodes 320A to 320E are plate-shaped (plate-shaped) is illustrated here, as shown in FIG. 15D, these are used as rod-shaped electrodes, and side surfaces extending in the longitudinal direction. Is preferably opposed to the electronic device P. Since the density of the electric lines of force is increased on the side surface of the rod-shaped electrode, it is possible to efficiently induce induction charging to the electronic device P.

  Next, an inspection apparatus 410 according to the fifth embodiment will be described with reference to FIGS. 16A and 16B. 16A is a side view of the inspection apparatus 410, and FIG. 16B is a front view of the inspection apparatus 410. Note that the last two digits of the reference numerals used in the illustration and description of the inspection apparatus 410 are the same as the reference numerals of the inspection apparatus 10 of the first embodiment, thereby omitting redundant description. The difference will be mainly described.

  In this inspection apparatus 410, a total of 25 application electrodes 420 are arranged in a matrix so as to face one surface of the electronic device P. Further, these application electrodes 420 are embedded in one insulator 424. As a result, the field emission surface 422 by the plurality of application electrodes 420 is connected to form one common field emission surface 428. In the common field emission surface 428, since the potential can be changed in a matrix shape over the entire surface direction, the electric field generated in the space near the electronic device P can be freely adjusted in a two-dimensional direction. A gradient can be formed.

  In particular, an electric field fluctuation unit (not shown) controls the supply voltages to these application electrodes 420 independently of each other. Specifically, the voltage is controlled so that the electric field moves in the vertical direction along the surface direction of the field emission surface 422.

  For example, when the electronic device P is an air traffic control panel, the inspection device 410 is disposed in front of the control panel, and an electric field that varies in the vertical direction is applied. As a result, it is possible to artificially create a situation where a user who is charged with static electricity operates the control panel while standing up or sitting down from the chair.

  Next, an inspection apparatus 510 according to the sixth embodiment will be described with reference to FIG. Note that the last two digits of the reference numerals used in the illustration and description of the inspection apparatus 510 are the same as the reference numerals of the inspection apparatus 10 of the first embodiment, thereby omitting redundant description. The difference will be mainly described.

  The inspection apparatus 510 has a structure in which a cylindrical application electrode 520 moves on a straight line by a self-propelled moving mechanism 580. The application electrode 520 is formed in a blade shape by crossing two aluminum plate electrodes in a cross shape. Further, the periphery of the application electrode 520 is covered with a cylinder 524 made of an insulating material such as ABS resin. By causing the application electrode 520 to run independently by the moving mechanism 580, for example, the influence of the application electrode 520 moving along the longitudinal direction can be inspected for an electronic device having a horizontally elongated structure.

  Next, an inspection apparatus 610 according to the seventh embodiment will be described with reference to FIG. 18A. Since this inspection apparatus 610 is characterized by the shape of the application electrode 620, it will be described in detail by limiting to the application electrode 620.

  The application electrode 620 of the inspection apparatus 610 includes a base electrode plate 621 and a plurality (four in this case) of plate electrode pieces 623A to 625A fixed to the base electrode plate 621 via spacers 621A. 623D. The four plate-like electrode pieces 623A to 623D are elongated strip-like plates, arranged side by side, and each plane faces the electronic device P. Further, these plate electrode pieces 623A to 623D are in a state of being energized with each other. That is, each plane of the plate-like electrode pieces 623A to 623D serves as a field emission surface piece, and by connecting these field emission surface pieces, one field emission surface 622 having the same potential is formed. As described above, even in one application electrode 620, by arranging a plurality of plate electrode pieces 623A to 623D, high-density electric lines of force emitted from the peripheral edges of the plate electrode pieces 623A to 623D are effectively used. Therefore, induction charging can be efficiently generated for the electronic device P.

  Further, for example, as shown in FIG. 18B, it is further preferable that the plate electrode pieces 623A to 623D are vertically arranged with respect to the base electrode plate 621. By doing in this way, each end surface of four plate-shaped electrode pieces 623A-623D can be made to oppose the electronic device P. FIG. As a result, each end surface of the plate-like electrode pieces 623A to 623D becomes a field emission surface piece, and these field emission surface pieces are connected to form one field emission surface 622 having the same potential. Compared with the example of FIG. 18A, since the end face having a high density of electric lines of force faces the electronic device P, it is possible to efficiently induce induction charging with respect to the electronic device P. Here, the state which rounded the end surface of plate-shaped electrode piece 623A-623D is shown. By rounding the end face in this way, corona discharge can be suppressed. On the other hand, when the end face has a sharp corner, corona discharge is likely to occur therefrom. The problem of corona discharge is as already described.

  18B illustrates the case where the plate-like electrode pieces 623A to 623D are erected with respect to the base electrode plate 621. However, as shown in FIG. 18C, the plurality of plate-like electrode pieces 623A to 623D are formed in a bar shape. Alternatively, a skewered state with a plate-like spacer material 629 is also preferable.

  18B illustrates the case where the base electrode plate 621 and the plate electrode pieces 623A to 623D are separate members, they may be integrally formed. Specifically, in this case, as shown in FIG. 18D, it can be understood that the band-shaped protrusions 625A to 625D are formed on the base electrode plate 621. Each protruding end of the band-shaped protrusions 625A to 625D becomes a band-shaped field emission surface piece. These strip-shaped field emission surface pieces are connected to form one field emission surface 622 having the same potential.

  18A to 18C exemplify the case where the application electrode 620 includes a plurality of plate-like electrode pieces 623A to 623D. However, as shown in FIG. 18E, the application electrode 620 includes a plurality of rod-like electrode pieces 625A to 625A. 625D is provided, and the side surfaces extending in the longitudinal direction of the respective rod-like electrode pieces 625A to 625D are also preferably opposed to the electronic device P. In this way, the side surfaces of the rod-shaped electrode pieces 625A to 625D become band-shaped field emission surface pieces, and these field emission surface pieces are connected to form one field emission surface 622 having the same potential. Note that the plurality of rod-shaped electrode pieces 625 </ b> A to 625 </ b> D are preferably skewed with a spacer material 629.

  In addition, in the said 1st-7th embodiment, although the raw material of an application electrode is not specifically limited, For example, it is preferable to use a high resistance material as a material of an application electrode. As the high resistance material, for example, a material having a volume resistivity of 100 (kΩ · m) or more is preferably selected, and ceramic or the like is preferable. In addition, it is desirable to use a high resistance wire (for example, a high resistance wire made of rubber) instead of a normal metal wire (copper wire) as the resistance value of the connection line that supplies a voltage to the application electrode. When such a high resistance material is selected, it is possible to suppress electromagnetic field radiation due to rapid current generation when a voltage is applied while applying a sufficient electric field to the electronic device P. As a result, it is possible to avoid confusion with the conventional ESD test by the ESD gun. That is, it is possible to positively induce a discharge phenomenon inside the electronic device P as required in the present invention. In addition, even if the operator touches the application electrode, it is possible to suppress the electric shock, and to increase the safety of the apparatus.

  Moreover, in the said embodiment, the kind of electronic device used as a to-be-measured object is not specifically limited. In addition to structures such as mobile phones, electronic computers, and automatic ticket gates, all components and materials used in electronic equipment such as IC chips, component mounting substrates, semiconductor devices, crystal devices, MEMS devices, and various electronic sensors are included.

  It should be noted that the present invention is not limited to the above-described embodiment, and it is needless to say that various modifications can be made without departing from the gist of the present invention.

Claims (18)

An electrostatic discharge detector for analyzing transient electromagnetic fields characteristic of induced ESD phenomenon,
An antenna for detecting the transient electromagnetic field;
A waveform analyzer for analyzing the waveform characteristics of the transient electromagnetic field based on the detection signal of the antenna;
From the analysis result of the waveform analysis unit, a discharge determination unit that determines the presence or absence of the induced ESD phenomenon based on whether the detection signal has a broadband characteristic or a repetitive generation characteristic;
An electrostatic discharge detection device comprising: The waveform analyzer
A first frequency analysis unit for determining whether or not a first frequency component is included in the detection signal;
A second frequency analysis unit for determining whether or not the detection signal includes a second frequency component different from the first frequency component;
The discharge determination unit
When the substantially same output waveform in the detection signal includes both the first and second frequency components, it is determined that the induced ESD phenomenon exists.
The electrostatic discharge detection device according to claim 1. A third frequency analysis unit that determines whether or not the detection signal includes a third frequency component different from the first and second frequency components;
The discharge determination unit
When the first, second and third frequency components are included in substantially the same output waveform in the detection signal, it is determined that the induced ESD phenomenon exists,
The electrostatic discharge detection device according to claim 2. The first frequency and the second frequency are set to two bands selected from an MF (medium wave) band, an HF (short wave) band, a VHF (very high frequency) band, and a UHF (very high frequency) band. Features
The electrostatic discharge detection apparatus according to claim 2 or 3. The first frequency component and the second frequency component are set to have a frequency difference of about 30 MHz or more,
The electrostatic discharge detection apparatus according to claim 2. The waveform analyzer
The detection signal includes a repetitive waveform analysis unit that determines whether or not a plurality of output waveforms are included,
The discharge determination unit
When the plurality of output waveforms are included, it is determined that the induced ESD phenomenon exists,
The electrostatic discharge detection apparatus according to claim 1. The repetitive waveform analysis unit determines whether the detection signal includes a plurality of output waveforms that are a predetermined number of times or more,
The discharge determination unit
When a plurality of output waveforms that are a predetermined number of times or more are included, it is determined that the induced ESD phenomenon exists,
The electrostatic discharge detection device according to claim 6. The waveform analyzer
A polarity analysis unit for determining whether an output waveform included in the detection signal is a positive waveform or a negative waveform;
The repetitive waveform analyzer counts the number of occurrences for each of the positive waveform and the negative waveform,
The discharge determination unit determines that the induced ESD phenomenon exists when the positive waveform is generated a plurality of times or when the negative waveform is generated a plurality of times,
The electrostatic discharge detection device according to claim 7 or 8. The antenna is a monopole antenna,
The electrostatic discharge detection apparatus according to claim 1. An applied electrode for exposing an electric field to an electronic device to be measured;
Electric field variation means for varying the strength of the electric field applied to the electronic device during inspection;
The electrostatic discharge detection device according to any one of claims 1 to 9,
With
By causing induction charging inside the electronic device due to fluctuations in the electric field during inspection, an induced ESD phenomenon occurs in the electronic device,
Detecting the induced ESD phenomenon with the electrostatic discharge detector;
Inspecting the operating characteristics of the electronic device based on the induced ESD phenomenon due to the induced charging,
Electronic device fluctuation electric field tolerance inspection device. The electric field variation means includes a voltage control device that varies the strength of the electric field by changing a voltage applied to the application electrode.
The apparatus for inspecting fluctuation electric field resistance of electronic equipment according to claim 10. The electric field fluctuation means increases the absolute value of the positive or negative electric field applied to the electronic device, thereby causing the first induction charging to the electronic device, and then the first of the electronic device. Resetting the potential of induction charging, and further reducing the absolute value of the positive or negative electric field, thereby causing the electronic device to generate a second induction charging in which the first induction charging is reversed from the first induction charging. Characterized by the
The fluctuation | variation electric field tolerance test | inspection apparatus of the electronic device of Claim 11. The application electrode is a plate electrode, and the plane of the plate electrode is opposed to the electronic device,
The fluctuation | variation electric field tolerance inspection apparatus of the electronic device in any one of Claims 10 thru | or 12. The application electrode is a plate electrode, and the end surface of the plate electrode is opposed to the electronic device.
The fluctuation | variation electric field tolerance inspection apparatus of the electronic device in any one of Claims 10 thru | or 12. The electric field fluctuation means includes a moving mechanism that changes a relative distance between the electronic device and the application electrode, and changes the strength and gradient of the electric field according to the change in the relative distance.
The apparatus for inspecting fluctuation of electric fields of electronic equipment according to claim 10. It comprises a synchronization control means for synchronizing the sensing timing of the electrostatic discharge detection device and the electric field fluctuation timing by the electric field fluctuation means,
The electronic device fluctuation electric field tolerance inspection apparatus according to claim 10. An electrostatic discharge detection and detection method for analyzing a transient electromagnetic field characteristic of an induced ESD phenomenon,
Detecting the transient electromagnetic field with an antenna;
A waveform analysis step of analyzing a waveform characteristic of the transient electromagnetic field based on a detection signal of the antenna;
From the analysis result of the waveform analysis step, based on whether the detection signal has a broadband characteristic or a repetitive occurrence characteristic, a discharge determination step of determining the presence or absence of the induced ESD phenomenon,
An electrostatic discharge detection method comprising: The waveform analysis step includes
A first frequency analysis step for determining whether or not a first frequency component is included in the detection signal;
A second frequency analysis step for determining whether or not the detection signal includes a second frequency component different from the first frequency component;
The discharge determination step includes
When the substantially same output waveform in the detection signal includes both the first and second frequency components, it is determined that the induced ESD phenomenon exists.
The electrostatic discharge detection method according to claim 17.

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