JP2004108991A - Failure diagnosis method and its system, and circuit board - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a system for diagnosing a failure of a circuit board with a convenient and inexpensive mechanism. <P>SOLUTION: A plurality of patterns 30 are formed on the circuit board 10 ranging from individual pins 22a of ICs 22 to an input/output part of the circuit board 10. A capacity component 40 consisting of metal members 40a, 40b is arranged crossing the plurality of patterns 30. A failure diagnosis part 90 is connected to the opening end of the two metal members 40a, 40b. The failure diagnosis part 90 detects an electric signal corresponding to a signal change induced in the capacity component 40 by electrostatic joint between the pattern 30 and the capacity component 40 as a result of the supply of power to the circuit board 10 followed by the operation of a circuit member 20. Whether the whole board is in failure or not is diagnosed by comparing the electric signal with a previously measured electric signal in a normal condition. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention predicts the operation, performance abnormality, or failure of a circuit member in a device having a circuit board on which a circuit member is mounted, for example, a printer device, a facsimile device, or a device such as a multifunction peripheral having those functions. The present invention relates to a method of detecting and detecting (hereinafter collectively referred to as a failure diagnosis), a failure diagnosis system for implementing the failure diagnosis method, and a circuit board used in the failure diagnosis system.
[0002]
[Prior art]
[Patent Document 1]
Japanese Patent Application Laid-Open No. H11-211800
[Patent Document 2]
JP-A-2000-74998
[Non-patent document 1]
Hisashi Fujishiro, Toshifumi Yamada, Masayoshi Iwahara, "Detection of Printed Wiring Defects by Eddy Current Testing", [online], [Searched September 1, 2002], Internet <URL: http: // magmac1. ec. t. kanazawa-u. ac. jp / magcap-j / research-j / ecta-j. html>
[0003]
2. Description of the Related Art In recent years, as electronic devices such as personal computers and copiers have been improved in performance and functions, analog and digital electronic circuits for various applications for realizing them have been increasingly stored in the form of printed circuit boards. .
[0004]
In addition, a number of electronic circuit boards with high reliability and high-speed and high-precision operation are mounted as means for operation control in other industrial devices such as automobiles, aviation, robots and semiconductor design devices. . These electronic circuit boards are connected via various cables in order to realize a series of functions, thereby achieving desired specifications.
[0005]
The environment in which the device on which such a board is mounted is used is usually in an office or a house, but it may be used in other harsh environments, and it is very diverse. Over. In particular, when the use environment is poor, various abnormalities and failures that are difficult to detect occur even if the device is used in a normal manner, and a great deal of labor is required to repair the abnormalities and failures.
[0006]
In addition, even when the electronic circuit is used in a normal use environment, an abnormality or a failure of the electronic circuit occurs, the frequency of the abnormality is not always low, and the detection location cannot often be specified. Further, when an abnormality occurs in the electronic circuit board, it is necessary to take an urgent action in terms of safety and cost.
[0007]
As a general method of fault diagnosis, a fault location is identified while monitoring (monitoring) the voltage and signal waveform of a main location using a measuring device such as a tester. However, in such a diagnostic method, it is necessary to perform measurement at various points, and trouble is required for trouble diagnosis, and there is a problem that work efficiency is poor.
[0008]
Therefore, as an efficient diagnosis method, there is a self-diagnosis system (Diagnostics system) in which the apparatus itself diagnoses each board when the apparatus is started. In this self-diagnosis system, for example, a signal pattern when the apparatus is operating is monitored for each circuit module or each board, and is compared with an expected value stored in advance to determine whether or not a failure has occurred. Is to be identified.
[0009]
For example, when a service center is notified of an error or failure information about a copier or printer, a repair person rushes to the site to repair the failure based on the failure location information and failure history information recorded on the equipment. Measures such as specifying the part, replacing it, or performing repair work may be taken. Alternatively, if these devices are connected to a network and automatically transmit status management, failure information, etc. to the department that manages these information, the information must be analyzed in advance and repaired. Similar actions may be taken by the person in charge.
[0010]
However, when the above-described abnormality or failure occurs, there is a disadvantage on the user side that the device is normally unusable and downtime occurs. Also, for the maker side, it takes much time to specify the faulty part, and the faulty part cannot always be specified accurately, and measures such as replacing all the parts considered to be faulty cause a great cost, Or there are situations in which repair itself takes time, and manpower-like responses cannot keep up. Therefore, there is a fact that both the user side and the maker side frequently suffer a great loss.
[0011]
Therefore, when identifying a failure part or predicting the occurrence itself, various abnormal states and failure states are fully understood, such as increasing the accuracy of identification and reducing the time loss until identification. Various attempts have been made on a method of implementing these configurations simply and at low cost.
[0012]
As a method for inspecting an electronic circuit board, a method using an image has been conventionally known, but today, as a new approach, an inspection method using an electrostatic coupling, an electromagnetic coupling, or an electro-optic effect has been proposed. .
[0013]
For example, Non-Patent Document 1 proposes a method of detecting a defect in a printed wiring using an eddy current flaw detection technique. This method uses an ultra-small and uniquely shaped magnetic field detection probe for detecting a magnetic field generated from a current flowing through a wiring serving as a target (a target part for failure diagnosis) as shown in FIG. This is a method of detecting an abnormality occurring in a substrate including a failure of an IC by a method of non-contact scanning of wiring of the substrate by a non-contact method. According to this method, disconnection or abnormal line width of the current high-density printed circuit board can be realized at high speed without mechanical stress.
[0014]
Further, as shown in FIG. 15, Patent Document 1 discloses an IC package probing device used for IC operation check and failure analysis corresponding to the recent increase in the density of IC package pins. In the failure detection method described in Patent Document 1, an attempt is made to realize efficient failure detection by forming a near-magnetic field probe group having the same arrangement as the lead terminals of the IC package.
[0015]
In addition, as shown in FIG. 16, in Patent Document 2, the current value of each board is read using a current sensor or the like, and is compared with a normal value stored in a memory to specify a failure portion and to quickly determine the location of a failure. A mechanism for realizing discovery has been proposed.
[0016]
In each of the methods described in Non-patent Document 1 and Patent Documents 1 and 2, the magnetic flux generated from the current flowing through the wiring of the circuit board and the inside of the mounted component is passed through the coil winding serving as a magnetic field sensing unit. Then, by reading the induced electromotive force generated in the magnetic field sensing unit, and comparing the read induced electromotive force with a previously measured induced electromotive force in a normal state, a method of diagnosing the presence or absence of a failure is described. In common.
[0017]
[Problems to be solved by the invention]
However, in each of Non-Patent Document 1 and Patent Documents 1 and 2, it is necessary to use an expensive dedicated probe (sensing probe) as a means for sensing a magnetic field, so that a failure detection cost is required.
[0018]
Further, in order to check the state of an arbitrary wiring or terminal of the sensing probe, it is necessary to bring the probe close to the vicinity and observe the state. This is because the range that can be detected by one probe is narrow, and it is necessary to bring the probe close to the diagnostic site for accurate diagnosis. Therefore, for example, as shown in FIG. 17, it is necessary to adopt a method of interposing a human hand as a means for bringing the probe closer to the target portion, or to move the probe using mechanical means. On the other hand, when such a moving method is not adopted, only the range near the fixed probe position can be detected, and the detection range becomes very narrow.
[0019]
As described above, the conventional failure diagnosis method is not always easy to use in terms of cost and the degree of freedom in setting the target part of the failure diagnosis.
[0020]
The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a failure diagnosis method capable of realizing an easy-to-use failure diagnosis mechanism at low cost.
[0021]
Another object of the present invention is to provide a failure diagnosis system for implementing the failure diagnosis method of the present invention, and a circuit board used for the failure diagnosis system.
[0022]
[Means for Solving the Problems]
That is, the failure diagnosis method according to the present invention is a failure diagnosis method for diagnosing the presence / absence of a failure of an electronic circuit system appearing on a signal line in an electronic circuit system, wherein a reactance component is provided near a signal line to be subjected to failure diagnosis. An electric signal corresponding to the signal change of the signal line induced in the reactance component by the electrostatic or electromagnetic coupling between the signal line and the reactance component is disposed non-contact and fixed to the signal line. By detecting and comparing the detected electric signal with an electric signal corresponding to a signal change in a normal state of the electronic circuit system obtained in advance, it was decided to diagnose the failure of the electronic circuit system. .
[0023]
Here, specific examples of the “signal line to be diagnosed” include a signal input / output terminal of a circuit member on a circuit board and a transmission line at an interface between a plurality of circuit boards. The transmission line at the interface between the plurality of circuit boards includes an input / output signal line to an input / output connector for providing a signal interface between the plurality of circuit boards, a signal cable of a wire harness, and the like.
[0024]
"Fixed arrangement" means that the physical positional relationship between the reactance component and the signal line to be diagnosed is maintained in a constant state. For example, in the case where a circuit board and a reactance component are physically fixed, or when applied to an apparatus having a plurality of boards, a signal cable and a reactance component for providing a signal interface between a plurality of circuit boards. Are physically integrated with each other.
[0025]
A failure diagnosis system according to the present invention is a system for performing the above-described failure diagnosis method according to the present invention, and includes a reactance non-contact and fixedly disposed with respect to a signal line near a signal line to be subjected to failure diagnosis. Component, and an electrical signal corresponding to a signal change of the signal line induced in the reactance component due to electrostatic or electromagnetic coupling between the signal line and the reactance component. A failure diagnostic unit for diagnosing the presence or absence of a failure in the electronic circuit system by comparing the acquired electronic signal with a signal corresponding to a signal change in a normal state of the electronic circuit system is provided.
[0026]
The dependent claims define further advantageous specific examples of the fault diagnosis system according to the present invention.
[0027]
The circuit board according to the present invention is a circuit board used in the failure diagnosis system according to the present invention, and is arranged in a non-contact and fixed manner with respect to the signal line in the vicinity of the signal line to be subjected to the failure diagnosis. And a reactance component for detecting an electric signal corresponding to a signal change of the signal line induced by electrostatic coupling or electromagnetic coupling with the signal line.
[0028]
[Action]
In the above configuration according to the present invention, first, the signal line, which is the target part of the failure diagnosis, is arranged in a non-contact and fixed manner. Then, an electric signal corresponding to the signal change of the signal line induced in the reactance component by the electrostatic or electromagnetic coupling between the signal line and the reactance component is read, and the read electric signal is measured in advance. By comparing the set electrical signal with a normal signal, it is diagnosed whether the wiring of the circuit board or the mounted component has a failure.
[0029]
While the design of the conventional detection probe required a dedicated one that required advanced technology to identify the failure site from a micro viewpoint, the reactance component of the present application that functions as a detection probe is By trying to determine the presence or absence of a failure from a macro perspective, it is possible to use a reactance component with a simple structure, and a simple structure in which this reactance component is fixedly arranged according to the failure diagnosis target site is sufficient. It is characterized by the following points.
[0030]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0031]
FIG. 1 is a diagram illustrating a first example of a basic configuration for realizing the present invention. Here, FIG. 1A shows an outline of a board layout and a failure diagnosis system. FIG. 1B shows an equivalent circuit of the circuit board 10 shown in FIG.
[0032]
As shown in FIG. 1A, a printed wiring pattern (hereinafter simply referred to as a pattern) 30 (not shown) is formed on a circuit board (an example of an electronic circuit system) 10 that constitutes the failure diagnosis system 1 at a predetermined corresponding position. , A circuit member 20 is mounted. The circuit member 20 may be a passive component such as a resistive element, an inductive element, or a capacitive element, or may be an active component such as a transistor or an IC (Integrated Circuit). Hereinafter, an example in which an IC 22 is mounted as the circuit member 20 will be described.
[0033]
A plurality of patterns 30 are formed from the individual pins 22a of the IC 22 on the circuit board 10 to the input / output unit of the circuit board 10. A capacitive component (capacitive reactance component) 40, which is an example of a reactance component, is arranged so as to intersect the plurality of patterns 30. As the capacitance component 40, two long thin metal members 40 a and 40 b are arranged in a line on the pattern 30 with a predetermined gap 40 c therebetween, and are close to and non-contact with the longitudinal direction of the plurality of patterns 30. And are fixedly arranged so as to intersect substantially orthogonally. It is preferable to use a taping member, an adhesive member, or the like for the fixed arrangement.
[0034]
A failure diagnostic unit 90 for detecting the presence or absence of a failure in the circuit board 10 is connected to the open ends (outside) of the two metal members 40a and 40b constituting the capacitance component 40. The failure diagnosis unit 90 configures the open end of the capacitance component 40 by crosstalk when the signal of each pattern 30 changes due to the power being supplied to the circuit board 10 and the operation of the circuit member 20 (the IC 22 in this example). A voltage (coupling voltage) Vo induced by electrostatic coupling (electrostatic coupling) between the metal members 40a and 40b, that is, the ends of the capacitance component 40 and the pattern 30 is measured. Then, the presence or absence of a failure in the circuit board 10, which is an example of the electronic circuit system, is diagnosed by comparing with a previously measured induced voltage in a normal state (that is, an expected value). By providing the failure diagnosis unit 90 on the circuit board 10, a self-diagnosis system in which the apparatus itself diagnoses the board at the time of starting the apparatus may be constructed.
[0035]
As shown in FIG. 1B, the equivalent circuit of the capacitance component 40 of the fault diagnosis system 1 having such a configuration is such that the capacitance component 40 is orthogonal to the respective patterns 30 connected to the individual pins 22a of the IC 22. Are placed in a state in which the metal members 40a and 40b constituting the above are arranged. A stray capacitance component 48 that causes crosstalk is formed between the two metal members 40 a and 40 b (lines) constituting the capacitance component 40 and each pattern 30.
[0036]
The two metal members 40a and 40b are arranged so as to be substantially divided into two with respect to the pattern 30 group of the diagnosis target portion, and the stray capacitance component 48 is added to each of the two metal members 40a and 40b constituting the capacitance component 40. The failure diagnostic unit 90 reads a voltage induced via the differential diagnosis unit as a differential voltage.
[0037]
FIG. 2 is a schematic diagram of the waveform of the induced voltage Vo across the capacitance component 40 in a state where power is supplied to the circuit board 10 of the failure diagnosis system 1 shown in FIG. 1. FIG. FIG. 2B is an example when the pattern 30 is in a normal state, and FIG. 2B is an example when the IC 22 or the pattern 30 is in an abnormal state and the signal change is not normal (abnormal).
[0038]
For example, when the circuit board 10 is operating normally, static characteristics as shown in FIG. That is, in the normal state, a waveform having four types of peaks, peak A, peak B, peak C, and peak D, is observed within the period of t11. A minute amplitude waveform of ± Vs is observed during the time when no peak appears.
[0039]
Here, in a situation where a part of the pattern 30 in FIG. 1 is broken due to a crack or the like, a part of the pattern 30 is in an open state, so that a wiring in which a signal does not flow occurs. Therefore, it also affects the time change of the voltage Vo due to the crosstalk phenomenon caused by the signal fluctuation.
[0040]
Therefore, since the voltage Vo changes with the fluctuation, a static characteristic as shown in FIG. 2B is obtained, for example. In FIG. 2B, four types of peaks within the period of t11 observed in FIG. 2A have no change in peak A, but peak B, peak C, and peak D are respectively The amplitude is very small like peak b, peak c, and peak d. Also, the amplitude of the minute amplitude waveform of ± Vs during the time when no peak occurs is very small.
[0041]
The failure diagnosis unit 90 determines whether an abnormality has occurred in the pattern 30 on the circuit board 10 by reading the difference between the peak potentials. That is, in the first example, the state of signal change of each pattern 30 is collectively measured by one capacitance component 40 and compared with a voltage waveform in a normal state to determine whether the circuit board 10 is in a normal state. Check.
[0042]
In the above-described example, the open state of the pattern 30 is described as an example of an abnormal state. However, a state in which the pattern 30 is short-circuited or the inside of the circuit member 20 (the IC 22 in this example) fails and does not operate (hereinafter, fails and does not operate). If a circuit member in a state is called a faulty member), the waveform state of the voltage Vo will be different from the above-described example of FIG. It becomes. Therefore, as described above, by comparing the waveform state of the voltage Vo in the normal state with the waveform state of the voltage Vo in the working state, it is possible to determine whether there is a short circuit of the pattern 30 or an internal failure of the circuit member 20. it can.
[0043]
The same applies to the other input / output units on the circuit board 10 in the same manner as described above, and by observing whether the signal of the board input / output unit is in the normal state, whether the circuit board 10 is in the normal state Can be confirmed.
[0044]
As described above, according to the basic configuration of the first example, a capacitance component, which is an example of a reactance component, is fixedly provided near the signal line of the circuit board by using a taping member or an adhesive member, and is connected to the signal line. By detecting the induced voltage generated in this capacitance component due to the electrostatic coupling between the two, it is possible to check for a fault by comparing the induced voltage during normal operation with the induced voltage during normal operation, which is obtained in advance. it can.
[0045]
A simple configuration in which an electrode member constituting a capacitance component is fixed near a diagnosis target portion on a substrate with a taping member or the like, and a physical positional relationship between the capacitance component 40 functioning as a sensing unit and the circuit board 10 is fixed. Can be. Thus, it is possible to reliably stabilize the state of the induced voltage during the failure diagnosis. That is, the induced voltage serving as a judgment index for failure diagnosis can be obtained with high accuracy, and the diagnostic performance is also improved.
[0046]
In addition, since the capacitance component 40 is fixedly arranged, it is needless to say that there is no need for a mechanical means for bringing the probe closer to the diagnosis location for observation or for bringing the probe closer to the target portion. Whereas the design of a conventional detection probe has attempted to identify a failure site from a microscopic viewpoint, the capacitance component 40 serving as a detection probe has a macroscopic viewpoint (in the previous example, a plurality of patterns 30 are grouped together). In order to determine the presence / absence of a failure in (1), a simple and low-cost structure in which the capacitance component 40 functioning as a detection probe is fixedly provided at a desired position on the substrate (in the vicinity of the diagnosis target site) is sufficient. It is characterized by the following points.
[0047]
Identify a faulty circuit board by arranging a capacitive component 40 at the interface between the boards and reading the state of each input / output signal of the circuit board and comparing it with a previously stored normal state. Can be. In addition, if the capacitance component 40 is arranged at the input / output terminal portion of each component, it is possible to diagnose the failure of each component.
[0048]
As described above, in the detection method using the electrostatic coupling, a load capacitance is always formed for an original signal line, which is a factor of deteriorating frequency characteristics. Therefore, care must be taken when applying the present invention to a signal line in which high-frequency components are exclusively transmitted and waveform dulling is not allowed. For example, it is preferable to provide a mechanism that disconnects the capacitance component 40 and the failure diagnosis unit 90 near the capacitance component 40 except for the time of the inspection, and brings the capacitance component 40 into a floating state.
[0049]
FIG. 3 is a diagram showing a modified example (hereinafter also referred to as a 1a example) of the first example shown in FIG. Here, FIG. 3A shows an outline of a board layout and a failure diagnosis system. FIG. 3B shows an equivalent circuit of the circuit board 10 shown in FIG.
[0050]
As shown in FIG. 3A, in the configuration of the first example, one long metal member 40 a is used as an electrode material forming the capacitance component 40, and the individual pins of the IC 22 on the circuit board 10 are provided. The pattern 30 is arranged so as to intersect with the plurality of patterns 30 formed in the pattern 22a and so as to intersect all of the patterns 30 in the portion to be diagnosed. The metal member 40a is arranged on the pattern 30 with a predetermined gap 40c therebetween and in close proximity to and non-contact with each pattern 30.
[0051]
A failure diagnosis unit 90 for detecting the presence or absence of a failure in the circuit board 10 is connected to one end of one metal member 40a constituting the capacitance component 40. The grounding portion of the circuit near the other end of the metal member 40a is connected to the failure diagnosis unit 90 in the same manner.
[0052]
As shown in FIG. 3B, the equivalent circuit of the capacitance component 40 of the failure diagnosis system 1 of the first example has a capacitance so as to be orthogonal to all the patterns 30 connected to the individual pins 22a of the IC 22. The state is such that the metal member 40a constituting the component 40 is arranged. A stray capacitance component 48 that causes crosstalk is formed between the metal member 40 (line) constituting the capacitance component 40 and each pattern 30.
[0053]
The failure diagnostic unit 90 reads a voltage induced via the stray capacitance component 48 in one metal member 40a provided for all the patterns 30 in the diagnosis target portion with reference to the ground potential of the circuit. It has become. In the basic configuration of the first example, as can be seen from the equivalent circuit shown in FIG. 1B, the voltage induced in each of the two metal members 40a and 40b forming the capacitance component 40 is regarded as a differential voltage and a failure occurs. This is different from the configuration in which the diagnosis unit 90 reads.
[0054]
As described above, although the mechanism for detecting the voltage induced on the electrode plate due to the crosstalk differs between the basic configuration of the first example and the first example, which is a modification thereof, the failure diagnosis unit 90 applies the detected voltage to the detected voltage. There is no difference in the mechanism itself for detecting the presence or absence of a failure in the circuit board 10 based on the above. By comparing the voltage waveform state in the normal state and the voltage state in the active state, a short circuit of the pattern 30 or a circuit member 20 can be determined whether there is an internal failure.
[0055]
As a further modification of the first example (hereinafter also referred to as a first example), instead of the ground portion of the circuit taken out from the vicinity of the other end of the metal member 40a connected to the failure diagnosis unit 90, A configuration for connecting to the other end of the metal member 40a itself may be adopted. In this case, the failure diagnosis unit 90 takes in the voltage induced in the metal member 40a using the internal impedance of the metal member 40a. If the internal resistance of the metal member 40a is zero, it is impossible to read the voltage induced in the metal member 40a at both ends. However, actually, since the internal resistance of the metal member 40a is not zero and has a considerable resistance component, it is impossible to read the voltage induced on the metal member 40a from both ends even in the connection mode as in the first example. It is possible.
[0056]
Further, as a development of the first example, as shown by a dotted line in the basic form of FIG. 1A and the modified example (first example) of FIG. A resistance element 49 having an appropriate resistance value may be inserted (hereinafter, such a configuration is collectively referred to as a 1c example). According to the configuration of Example 1c, there is an advantage that the detection sensitivity can be adjusted by adjusting the resistance value.
[0057]
FIG. 4 is a diagram illustrating a second example of a basic configuration for realizing the present invention. The capacitance component 44 is arranged perpendicular to the single line (hereinafter, referred to as microstrip line) 32 connected to the input / output unit of the circuit board 10 and the front and back surfaces of the circuit board 10. Here, "the capacitance component 44 is perpendicular to the front surface and the back surface of the circuit board 10" means that the input / output terminal of the signal (induced voltage) extracted by the capacitance component 44 is orthogonal to the substrate surface. Meaning.
[0058]
As the capacitance component 44, two flat plate-like metal members 44a and 44b are arranged close to the microstrip line 32 in a non-contact manner with a predetermined gap 44c therebetween. The metal members 44a and 44b are formed by a printed wiring pattern on a surface different from the circuit pattern of the circuit board 10 by using an inner layer surface of the circuit board 10, for example. This is to prevent the wiring design of the circuit pattern of the circuit board 10 from being affected. Further, the electrode material for forming the capacitance component 44 by the printed wiring pattern can be formed simultaneously with the manufacture of the circuit board, so that the total manufacturing cost can be reduced.
[0059]
A failure diagnosis unit 90 for detecting the presence or absence of a failure in the circuit board 10 is connected to the open ends of the two metal members 44a and 44b constituting the capacitance component 44. As in the first example, the failure diagnosis unit 90 is configured to supply the power to the circuit board 10 and operate the circuit member 20 connected to the microstrip line 32 to change the signal of the microstrip line 32 when the signal of the microstrip line 32 changes. The voltage Vo induced at the metal members 44a and 44b constituting the open ends of the capacitance component 40, that is, at both ends of the capacitance component 44 due to the typical crosstalk is measured. Then, the presence / absence of a failure in the circuit board 10 is diagnosed by comparing the induced voltage in a normal state (that is, an expected value) measured in advance.
[0060]
In this second example, the circuit board 10 is in a normal state by measuring the state of signal change by the corresponding microstrip line 32 for each microstrip line 32 and comparing the measured signal change with the voltage waveform in a normal state. This is different from the first example in that it is checked whether or not it is.
[0061]
FIG. 5 is a diagram illustrating a first example (hereinafter referred to as a first specific example) of a specific example of the failure diagnosis system using the mechanism illustrated in FIGS. 1 and 4. The failure diagnosis system 1 of the first specific example is applied to failure diagnosis when a capacitance component for detecting a board abnormality is arranged on a surface of the circuit board 10 different from the surface on which the pattern 30 is formed. Is shown.
[0062]
For example, in the case where the first example described above is employed as the detection mode of the induced voltage, when the pattern 30 which is the diagnosis target portion is arranged on the surface of the circuit board 10, the electrode member 40a constituting the capacitance component 40 Is preferably arranged on the back surface different from the front surface. That is, on the back surface 70, the electrode member 40a constituting the capacitance component 40 which is an example of the reactance component is arranged at a predetermined position. Then, wiring is provided so that both ends of the electrode member 40a can be connected to the failure diagnosis unit 90. The mode of detecting the induced voltage is not limited to the first example, and the first example, which is a basic form, the first example, or the first example, which is a modification thereof, may be employed.
[0063]
The installation position of the electrode member 40 a configuring the capacitance component 40 is a position facing the failure diagnosis target site on the circuit board 10. For example, it is set to a position facing a position where a signal input / output connector 24 (two positions in the figure) as an example of a circuit member is disposed.
[0064]
The procedure for knowing the state of the circuit board 10 (presence or absence of a failure) from the waveform generated by the crosstalk phenomenon at both ends of the capacitance component 40 is the same as in the first and second examples in the above-described basic configuration.
[0065]
FIG. 6 is a diagram illustrating a second example (hereinafter, referred to as a second specific example) of a specific example of the failure diagnosis system using the mechanism illustrated in FIGS. 1 and 4. The failure diagnosis system 1 of the second specific example has a configuration in which a capacitance component 40 which is an example of a reactance component is embedded in the connector 24 of the board input / output unit.
[0066]
The connector 24 is arranged on the circuit board 10 at an interface with the outside of the pattern 30. The capacitance component 40 is installed so as to be substantially orthogonal to the longitudinal direction of the plurality of signal cables 26 and the lead pattern 30 provided in the connector 24. The connector 24 is provided with cables 28 a and 28 b for guiding a voltage Vo for failure detection induced by crosstalk to the capacitance component 40 to the failure diagnosis unit 90 together with the signal cable 26. In addition, as a detection form of the induced voltage, any of the above-described first example and the modified examples 1a, 1b, and 1c may be adopted, and the electrode member may be changed according to the adopted form. It should just be arranged.
[0067]
The voltage Vo for failure detection induced by crosstalk at both ends of the capacitance component 40 is extracted to a failure diagnosis unit 90 provided outside using the cables 28a and 28b prepared in the connector 24. I do.
[0068]
According to the configuration of the second specific example, it is possible to detect a failure state of a signal line very close to an interface portion between boards. Therefore, disconnection or short-circuit of the wire harness connecting the substrates can be more reliably detected.
[0069]
FIG. 7 is a diagram showing a third example (hereinafter, referred to as a third specific example) of a specific example of the failure diagnosis system using the mechanism shown in FIGS. 1 and 4. The failure diagnosis system 1 of the third specific example is used for failure diagnosis when a plurality of (three in the figure) circuit boards, which are examples of an electronic circuit system, are connected by a wire harness (including a flexible board, the same applies hereinafter). An example of the application is shown. Here, FIG. 7A is a diagram illustrating a system configuration, and FIG. 7B is a diagram illustrating a flow of signal processing between circuit boards in the configuration illustrated in FIG. 7A.
[0070]
As shown in FIG. 6A, input / output connectors 50, 52, and 54 are provided on the circuit boards 10, 12, and 14, respectively. The two circuit boards 12 and 14 are connected in parallel to the circuit board 10 via a wire harness 56.
[0071]
Circuit members are mounted in the regions 10a and 10b indicated by oblique lines on the circuit board 10 and the regions 12a indicated by oblique lines on the circuit substrate 12. Hereinafter, an example will be described in which ICs 82 and 84 are arranged in the areas 10a and 10b, and an IC 86 is arranged in the area 12a.
[0072]
In the vicinity of the input / output connectors 50, 52, 54 of the circuit boards 10, 12, 14, capacitance components 40, 42, 44 are arranged so as to be orthogonal to the pattern 30 connected to the respective connectors. The failure diagnosis unit 90 monitors the potentials V40, V42, and V44.
[0073]
The flow of signal processing is as shown in FIG. That is, the signal input to the IC 82 on the circuit board 10 is processed in the IC 82 (S100), and is input to the IC 86 on the circuit board 12 via the signal line 56a of the wire harness 56 (S102). The signal processed by the IC 86 is input to the IC 84 mounted on the circuit board 10 via the signal line 56b of the wire harness 56 and processed (S104). The signal processed by the IC 84 is then transferred to the circuit board 14 via the signal line 56c of the wire harness 56 (S106).
[0074]
8 is a schematic diagram of the waveform of the induced voltage V40 at both ends of the capacitance component 40 in the configuration shown in FIG. 7, in which FIG. 8A shows an example in a normal state, and FIG. It is an example. The measurement error by the failure diagnosis unit 90 is ± 1 mV. Note that the abnormal state in this example refers to a case where a failure 88 has occurred in the IC 84 on the circuit board 10 and the signal processing function has been totally lost.
[0075]
As shown in FIG. 8A, the static characteristics of the induced voltage V40 at both ends of the capacitance component 40 in the normal state are represented by amplitudes of −90 mV to +100 mV, ± 60 mV, and −30 mV to +35 mV at a cycle of 1 μs. Kinds of peaks are observed on small fluctuations of about ± 5 mV.
[0076]
Here, when a failure 88 occurs in the IC 84 on the circuit board 10, the three circuit boards 10, 12, and 14 perform signal processing in a system as shown in FIG. 6B. , 88. For this reason, the induced voltages V40, V42, and V44 detected by the crosstalk by the capacitance components 40, 42, and 44 disposed near the input / output connectors 50, 52, and 54 differ from those in the normal state (the waveform changes). )there is a possibility.
[0077]
For example, as shown in FIG. 8B, among the three types of peak waveforms observed in the normal state, the waveform having an amplitude of ± 60 mV is observed in the induced voltage V40 at both ends of the capacitance component 40. Is no longer being done. Therefore, the failure diagnosis unit 90 monitors the induced voltage V40 at both ends of the capacitance component 40, and compares the waveform state of the voltage V40 in the normal state with the waveform state of the voltage V40 in the working state, so that the three circuit boards It is possible to determine the presence or absence of a failure in the device consisting of 10, 12, and 14.
[0078]
9A and 9B are schematic diagrams of the waveform of the induced voltage V42 at both ends of the capacitance component 42 in the configuration shown in FIG. 7. FIG. 9A shows an example in a normal state, and FIG. It is an example. 8B, a failure 88 occurs in the IC 84 on the circuit board 10 and the signal processing function is completely lost.
[0079]
As shown in FIG. 9A, two kinds of peaks are observed at a period of 500 ns as static characteristics of the induced voltage V42 at both ends of the capacitance component 42 in the normal state, and amplitudes of −70 mV to +75 mV and ± 65 mV, respectively. Appear on a small fluctuation of about ± 5 mV.
[0080]
As shown in FIG. 9B, no difference is observed in the induced voltage V42 between both ends of the capacitance component 42 in the abnormal state as compared with the normal state. Therefore, the failure diagnosis unit 90 monitors the induced voltage V42 at both ends of the capacitance component 42, and compares the waveform state of the voltage V42 in the normal state with the waveform state of the voltage V42 in the working state. It is not possible to determine the presence or absence of a failure in the device consisting of 10, 12, and 14.
[0081]
FIG. 10 is a schematic diagram of the waveform of the induced voltage V44 at both ends of the capacitance component 44 in the configuration shown in FIG. 7, in which FIG. 10A shows an example in a normal state, and FIG. It is an example. 8B, a failure 88 occurs in the IC 84 on the circuit board 10 and the signal processing function is completely lost.
[0082]
As shown in FIG. 10A, three types of static characteristics of the induced voltage V44 at both ends of the capacitance component 44 in the normal state, which are represented by ± 40 mV, −25 mV to +30 mV, and amplitudes of ± 10 mV at a cycle of 800 ns, respectively. The peak is observed on a small fluctuation of about ± 5 mV.
[0083]
As shown in FIG. 10B, in the induced voltage V44 at both ends of the capacitance component 44 in the abnormal state, similarly to the induced voltage V40 of the capacitance component 40, of the three types of peak waveforms observed in the normal state, It has been observed that the amplitudes of the two types of peak waveforms except for the peak waveform having a minimum amplitude of ± 10 mV are reduced. Therefore, the failure diagnosis unit 90 monitors the induced voltage V44 at both ends of the capacitance component 44, and compares the waveform state of the voltage V44 in the normal state with the waveform state of the voltage V44 in the working state, thereby obtaining three circuit boards. It is possible to determine the presence or absence of a failure in the device consisting of 10, 12, and 14.
[0084]
As described above, in the configuration example of the signal processing system as shown in FIG. 7, it is observed that the waveforms of V40 and V44 among the induced voltages V40, V42, and V44 are not normal, and it is determined that some abnormality exists in the device. You can judge. However, it is difficult to identify which of the three circuit boards 10, 12, and 14 has the cause of the failure.
[0085]
Here, a detailed examination will be made in comparison with the signal processing flow shown in FIG. The fact that no abnormality is observed in the induced voltage V42 means that the signal processed by the IC 82 on the circuit board 10 is normally transmitted to the IC 86 of the circuit board 12 and is processed on the circuit board 12 in a normal manner. A process in which a signal processed by the IC 86 of the substrate 12 is normally transmitted to the circuit board 10, but a signal processed by the IC 84 on the circuit board 10 is transferred to the circuit board 14 and processed on the circuit board 14. This means that abnormalities are seen.
[0086]
Here, assuming that there is no abnormality in the input of the circuit board 14, it can be considered that an abnormality has occurred in the circuit board 10, which is an upstream part of the circuit board 14. In other words, the failure mode of the present example accurately represents a state in which the failure 88 has occurred in the IC 84 on the circuit board 10 and the signal processing function has been completely lost.
[0087]
As described above, when an induced voltage at an interface portion between boards is detected for each board in an apparatus configured with a plurality of circuit boards, abnormalities can be determined by linking with a signal processing sequence in the apparatus. The location (in the previous example, the board where a failure has occurred) can be accurately specified.
[0088]
FIG. 11 is a diagram illustrating a fourth example (hereinafter, referred to as a fourth specific example) of a specific example of the failure diagnosis system using the mechanism illustrated in FIGS. 1 and 4. Here, FIG. 11A is a system configuration diagram, and FIGS. 11B and 11C are diagrams illustrating a method of fixing an electrode member.
[0089]
The failure diagnosis system 1 of the fourth specific example is an example of application to failure diagnosis when a plurality of (three in the figure) circuit boards are connected by a wire harness (including a flexible board, the same applies hereinafter) or the like. 1 shows a modification of the configuration of FIG.
[0090]
In the configuration of FIG. 7, the electrode members constituting the capacitance component, which is an example of the reactance component, are arranged in the pattern portion of the inter-substrate interface of each circuit board. And that they are provided integrally.
[0091]
As shown in FIG. 10A, in the failure diagnosis system 1, three circuit boards 10, 12, and 14 are cascaded via a connector 24 on the board and a wire harness 52. Here, for example, in the case where the above-described first example is employed as the detection mode of the induced voltage, the electrode member 40a constituting the capacitance component 40 is connected to the individual signal cable 57 for the normal signal line of the wire harness 52. Are arranged so as to intersect so as to be substantially orthogonal to the longitudinal direction. Since each signal cable 57 is covered with the covering material, there is no possibility that the core wire of the signal cable 57 and the electrode member 40a are short-circuited without taking any special measures.
[0092]
As shown in FIGS. 11B and 11C, a failure diagnosis unit 90 for detecting the presence or absence of a failure in the circuit boards 10, 12, and 14 is connected to both ends of the electrode member 40a. ing. The mode of detecting the induced voltage is not limited to the first example, and the first example, which is a basic form, the first example, or the first example, which is a modification thereof, may be employed.
[0093]
It is preferable that the electrode member 40a and the wire harness 52 are fixed by a predetermined method so that the physical positional relationship between the signal cable 57 for a normal signal line and the electrode member 40a is stabilized.
[0094]
For example, as shown in FIG. 11B, a method of integrally covering the signal cable 57 for a normal signal line and the electrode member 40a with the covering material 52a may be adopted. The cable for detecting the induced voltage connecting the electrode member 40a and the failure diagnosis unit 90 may be covered with the covering material 52a.
[0095]
By doing so, the capacitance component, which is an example of the reactance component, can be housed and integrated in the wire harness (cable) connected to the connector constituting the board input / output unit interface, and induced during the failure diagnosis. Since the state of the voltage can be reliably stabilized, the diagnostic performance is improved. In addition, it is possible to avoid a possibility that the electrode member 40a is short-circuited with another member in the device.
[0096]
In addition, as shown in FIG. 11C, a method is adopted in which the signal cable 57 for a normal signal line and the electrode member 40a are united by co-fastening with a fastening member such as a taping member 52b or a binding band. Is also good. In this case, it is preferable that the entirety of the electrode member 40a be covered with the taping member 52b in order to avoid a possibility that the electrode member 40a and other members in the apparatus are short-circuited.
[0097]
FIG. 12 is a diagram illustrating a modification of the method of arranging the electrode members constituting the capacitance component, which is an example of the reactance component.
[0098]
In each of the above-described examples, as shown in FIG. 12A, the electrode member 40a constituting the capacitance component is moved in the longitudinal direction of the pattern 30 or the signal cable 57 of the wire harness, which is a member to be subjected to failure diagnosis. , Are arranged so as to intersect so as to be substantially orthogonal to each other in a close and non-contact state. By doing so, the plurality of patterns 30 and the signal cables 57 can be electrostatically coupled at the same time, so that there is an advantage that the induced voltage due to the electrostatic coupling can be detected by one capacitance component 40 at the same time.
[0099]
However, as shown in FIG. 4, a capacitance component may be arranged for each pattern 30 and each signal cable 57 (that is, signal line), and the arrangement of the electrode member 40a is not necessarily limited to such an arrangement. Not exclusively. For example, as shown in FIG. 12 (B), the electrode members 40a constituting the capacitance component are arranged in parallel with each other in a close and non-contact state with respect to the longitudinal direction of the pattern 30 or the signal cable 57 which is a member for failure diagnosis. May be arranged. In the case where the electrodes are completely arranged in parallel, it is necessary to provide the electrode member 40a constituting the capacitance component for each signal line. However, there is an advantage that the presence or absence of an abnormality can be separately detected for each signal line.
[0100]
Alternatively, as shown in FIG. 12C, the signal line and the electrode member 40a may be arranged so as to obliquely intersect. In this case, as in the case of the orthogonal arrangement shown in FIG. 12A, the plurality of patterns 30 and the signal cables 57 can be electrostatically coupled at the same time, and the induced voltage due to this can be reduced to one capacitance component. The advantage of being able to detect simultaneously at 40 is obtained.
[0101]
Further, in the embodiment shown in FIG. 12C, the area of the signal line and the electrode member 40a facing each other changes depending on the inclination angle Δ, so that the induced voltage Vo detected by the failure diagnosis unit 90 can also change. Therefore, by changing the inclination angle Δ, the coupling strength can be adjusted. In this case, the inclination angle may be set in a state where the detection voltage as a whole becomes large, or may be set so that a peak portion that requires special attention is maximized.
[0102]
FIG. 13 is a diagram illustrating a third example of a basic configuration for realizing the present invention. Each of the above-described cases (basic configurations of the first and second examples and their specific examples) includes an electrode member forming a capacitance component (capacitive reactance component), which is an example of a reactance component, and a signal line (printed wiring pattern and / or the like). This is a mechanism in which the presence or absence of a failure is determined by detecting a voltage induced on an electrode member constituting a capacitance component by electrostatic coupling with the signal cable). The difference is in the use of dynamic coupling.
[0103]
For example, as shown in FIG. 13, focusing on the input / output interface connector 24 as a specific mounting part on the circuit board 10, this is an example of a reactance component so as to surround the input / output interface connector 24. An inductance component (inductive reactance component) 41 is arranged. In the illustrated example, the printed wiring pattern is formed as a one-turn coil. However, the present invention is not limited to this, and the pattern coil may be formed so as to be wound plural times. The open end of the inductance component 41 is connected to the failure diagnosis unit 90.
[0104]
In the third embodiment, electromagnetic coupling is generated between the magnetic field (total) generated by the input / output interface signal in the input / output interface connector 24 and the inductance component 41, thereby generating the inductance component 41. A detection signal is obtained at both ends (open ends) of. The failure diagnosis unit 90 diagnoses the presence or absence of a signal failure at the interface pin (signal line) by detecting the induced electromotive force induced in the inductance component 41.
[0105]
In the illustrated example, the coil (the inductance component 41) is formed so as to collectively detect a plurality of pins. However, the coil may be formed for each pin and detected independently.
[0106]
In addition, in each embodiment using the electrostatic coupling, for example, the relationship between the orientation of the inductance component 41 and the signal line or the insertion of a resistance element having an appropriate resistance value between the connection line leading to the failure diagnosis unit. The items described above can be applied to the form using the electromagnetic coupling in almost the same manner, with a change corresponding to the electromagnetic coupling.
[0107]
Whether to use the electrostatic coupling or the electromagnetic coupling may be determined from the following viewpoint in relation to the frequency component of the voltage fluctuation of the signal line. In the form using the capacitive coupling, it is considered that the higher the frequency, the lower the impedance and the lower the detection sensitivity. On the other hand, in the form using electromagnetic coupling, it is considered that the lower the frequency, the lower the impedance and the lower the detection sensitivity. Therefore, in order to perform accurate detection, electrostatic coupling may be used when the frequency component of the voltage fluctuation of the signal line is mainly low frequency, and electromagnetic coupling may be mainly used when the frequency component is high frequency. In practice, however, this is not always the case, and it is better to decide by cut and try (trial and error).
[0108]
As described above, the present invention has been described using the embodiment. However, the technical scope of the present invention is not limited to the scope described in the embodiment. Various changes or improvements can be made to the above-described embodiment without departing from the spirit of the invention, and embodiments with such changes or improvements are also included in the technical scope of the present invention.
[0109]
Further, the above embodiments do not limit the invention according to the claims (claims), and all combinations of the features described in the embodiments are not necessarily essential to the means for solving the invention. Absent. The embodiments described above include inventions at various stages, and various inventions can be extracted by appropriately combining a plurality of disclosed constituent features. Even if some components are deleted from all the components shown in the embodiment, as long as the effect is obtained, a configuration from which some components are deleted can be extracted as an invention.
[0110]
For example, in the above-described embodiment, it is mentioned that the presence or absence of a failure is determined by detecting a difference in waveform shape (difference from a normal state) in the amplitude of a peak waveform. However, the present invention is not limited to this. It is also possible to determine the presence or absence of a failure based on the pulse width, or in the case of a waveform having no peak, the fluctuation of its absolute value.
[0111]
In the above embodiment, the waveform itself as raw data was handled. However, when it is extremely difficult to observe the waveform with high accuracy as it is, such as a high-frequency signal, processing such as rectification and amplification of the waveform is performed. Differences can also be found.
[0112]
Further, as another means for processing the raw data, a difference may be obtained as frequency information such as Fourier transform, or a difference may be obtained from a statistical method using an MTS (Maharanobis-Taguchi-System) method or the like. it can.
[0113]
Further, as is apparent from the above description, the following configuration can be proposed as an invention as a substrate used in the failure diagnosis system. These are listed below.
[0114]
<Supplementary Note 1> A circuit board used in the failure diagnosis system described in the above embodiment, which is arranged in a non-contact and fixed manner with respect to the signal line in the vicinity of the signal line to be subjected to failure diagnosis. A circuit board, comprising: a reactance component for detecting an electric signal corresponding to a signal change of the signal line induced by electrostatic or electromagnetic coupling with the signal line.
[0115]
<Supplementary Note 2> The circuit board according to Supplementary Note 1, wherein the reactance component is a capacitive reactance component that forms the electrostatic coupling with the signal line.
[0116]
<Supplementary Note 3> The circuit board according to supplementary note 1, wherein the reactance component is an inductive reactance component that forms the electromagnetic coupling with the signal line.
[0117]
<Supplementary Note 4> The supplementary notes 1 to 3, wherein a resistance component is inserted in a transmission line between the reactance component and the failure diagnosis unit for an electric signal detected by the reactance component. The circuit board according to any one of the above.
[0118]
<Supplementary Note 5> The circuit board according to any one of Supplementary Notes 1 to 4, wherein the reactance component includes a plate-shaped electrode member arranged to face the signal line. .
[0119]
<Supplementary Note 6> The circuit board according to supplementary note 5, wherein the electrode member is formed by a printed wiring pattern on the circuit board.
[0120]
<Supplementary Note 7> The circuit board is a multilayer board formed by stacking a plurality of boards,
The printed wiring pattern forming the electrode member is formed on an inner layer surface of the multilayer substrate and is different from a layer on which the printed wiring pattern for the signal line is arranged. The circuit board according to claim 1.
[0121]
<Supplementary Note 8> The electrode member corresponds to a signal change of the plurality of signal lines induced in the electrode member by the electrostatic coupling or the electromagnetic coupling between the plurality of signal lines and the electrode member. The signal lines are arranged so as to intersect with the plurality of signal lines so that the respective electric signals can be simultaneously detected. Circuit board.
[0122]
<Supplementary note 9> The circuit board according to any one of supplementary notes 1 to 8, wherein the reactance component is provided for the signal line in an interface portion between a plurality of circuit boards.
[0123]
<Supplementary Note 10> The circuit board according to supplementary note 9, wherein the reactance component is disposed inside a connector provided for the interface portion.
[0124]
【The invention's effect】
As described above, according to the present invention, a capacitance component or an inductance component, which is an example of a reactance component, is placed in the vicinity of a signal line such as a printed wiring pattern on a substrate or a signal cable of a wire harness by using a taping member or an adhesive member. It is provided fixedly using a printed wiring pattern, etc., detects the signal generated in the reactance component due to electrostatic or electromagnetic coupling with the signal line, and operates with the previously acquired normal signal. By comparing the detection signal at that time, the presence or absence of a failure in the electronic circuit system is checked.
[0125]
A simple and low-cost configuration in which a capacitance component and an inductance component, which are examples of a reactance component, are fixedly provided using a taping member, an adhesive member, a printed wiring pattern, or the like. The physical positional relationship of the cables can be fixed. Thus, the state of the detection signal during the failure diagnosis can be reliably stabilized. That is, it is possible to accurately acquire a signal induced in a reactance component serving as a determination index for failure diagnosis, and to improve diagnostic performance.
[0126]
In addition, since the reactance component is fixedly arranged, there is no need for a mechanical means for bringing the probe closer to the diagnostic location for observation or for bringing the probe closer to the target site. Even if a reactance component having a simple structure composed of a flat plate electrode or the like is provided at each location according to the diagnosis target site, the cost does not increase much.
[0127]
As a result, it is possible to provide a user-friendly failure diagnosis mechanism in terms of cost and the degree of freedom in setting a failure diagnosis target portion.
[Brief description of the drawings]
FIG. 1 is a diagram illustrating a first example of a basic configuration for realizing the present invention.
FIG. 2 is a schematic diagram of a waveform of an induced voltage Vo of a capacitance component in a state where power is supplied to a circuit board of the failure diagnosis system shown in FIG. 1;
FIG. 3 is a diagram showing a modification of the first example shown in FIG.
FIG. 4 is a diagram illustrating a second example of a basic configuration for realizing the present invention.
FIG. 5 is a diagram showing a first specific example of a failure diagnosis system using the mechanism shown in FIGS. 1 and 4.
FIG. 6 is a diagram showing a second specific example of the failure diagnosis system using the mechanism shown in FIGS. 1 and 4.
FIG. 7 is a diagram showing a third specific example of the failure diagnosis system using the mechanism shown in FIGS. 1 and 4.
8 is a schematic diagram of a waveform of an induced voltage V40 at both ends of a capacitance component 40 in the configuration shown in FIG.
9 is a schematic diagram of a waveform of an induced voltage V42 at both ends of a capacitance component 42 in the configuration shown in FIG.
10 is a schematic diagram of a waveform of an induced voltage V44 at both ends of a capacitance component 44 in the configuration shown in FIG.
FIG. 11 is a diagram showing a fourth example of a specific example of the failure diagnosis system using the mechanism shown in FIGS. 1 and 4.
FIG. 12 is a diagram illustrating a modified example of a method of arranging electrode members constituting a capacitance component which is an example of a reactance component.
FIG. 13 is a diagram illustrating a third example of a basic configuration for realizing the present invention.
FIG. 14 is a diagram showing an example of a probe used in a conventional failure diagnosis mechanism (cited from Non-Patent Document 1).
FIG. 15 is a diagram showing another example of a probe used in a conventional failure diagnosis mechanism (cited from Patent Document 1).
FIG. 16 is a diagram showing another example of a probe used in a conventional failure diagnosis mechanism (cited from Patent Document 2).
FIG. 17 is a diagram showing an outline of a mechanism for bringing a probe closer to a target site by interposing a human hand.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Fault diagnosis system, 10 ... Circuit board, 14 ... Circuit board, 20 ... Circuit member, 24 ... Connector, 30 ... Pattern, 32 ... Microstrip line, 40,44 ... Capacitance component, 40a, 40b ... Metal member, 41 ... Inductance component, 48 ... Stray capacitance component, 56 ... Wire harness, 90 ... Fault diagnosis unit

Claims (14)

A failure diagnosis method for diagnosing a failure of an electronic circuit system appearing on a signal line in an electronic circuit system,
A reactance component is arranged in a non-contact and fixed manner with respect to the signal line in the vicinity of the signal line to be subjected to the failure diagnosis, and an electrostatic or electromagnetic coupling between the signal line and the reactance component is provided. Detecting an electrical signal corresponding to a signal change of the signal line induced by the reactance component; and detecting the detected electrical signal and an electrical signal corresponding to the previously obtained signal change in a normal state of the electronic circuit system. A failure diagnosis method characterized by diagnosing a failure of the signal line by comparing the signal with a signal. A failure diagnosis system for diagnosing the presence or absence of a failure of an electronic circuit system appearing on a signal line in the electronic circuit system,
A reactance component non-contact and fixedly arranged with respect to the signal line in the vicinity of the signal line to be subjected to failure diagnosis;
Detecting an electric signal corresponding to a signal change of the signal line induced in the reactance component by electrostatic coupling or electromagnetic coupling between the signal line and the reactance component, and the detected electric signal; A failure diagnostic unit for diagnosing the presence or absence of a failure in the signal line by comparing a previously acquired electrical signal corresponding to the signal change when the electronic circuit system is normal, Fault diagnosis system. The fault diagnosis system according to claim 2, wherein the reactance component is a capacitive reactance component that forms the electrostatic coupling with the signal line. The fault diagnosis system according to claim 2, wherein the reactance component is an inductive reactance component that forms the electromagnetic coupling with the signal line. The resistance component is inserted in a transmission line between the reactance component and the failure diagnosis section for an electric signal detected by the reactance component. 2. The failure diagnosis system according to claim 1. The failure diagnosis system according to any one of claims 2 to 5, wherein the reactance component includes a plate-like electrode member arranged to face the signal line. The failure diagnosis system according to claim 6, wherein the electrode member is formed on a circuit board by a printed wiring pattern. The circuit board is a multilayer board formed by stacking a plurality of boards,
The said printed wiring pattern which comprises the said electrode member is formed in the layer different from the layer in which the printed wiring pattern for the said signal lines is arrange | positioned at the inner layer surface of the said multilayer substrate. 8. The failure diagnosis system according to 7. The electrode member is arranged to intersect the plurality of signal lines,
The failure diagnosing unit corresponds to a signal change of the plurality of signal lines induced in the electrode member by the electrostatic coupling or the electromagnetic coupling between the plurality of signal lines and the electrode member. The fault diagnosis system according to any one of claims 6 to 8, wherein the electrical signals are detected simultaneously. 10. The fault diagnosis system according to claim 2, wherein the reactance component is provided for the signal line at an interface between a plurality of circuit boards. The failure diagnosis system according to claim 10, wherein the reactance component is disposed inside a connector provided for the interface portion. The failure diagnosis system according to claim 10, wherein the reactance component is provided integrally with a wire harness provided for the interface portion. The failure diagnosis unit is configured to determine whether there is a failure in the plurality of circuit boards based on a signal processing sequence between the plurality of circuit boards and an electric signal corresponding to the detected signal change of the signal line. The failure diagnosis system according to claim 10, wherein the board is specified. A circuit board used for the failure diagnosis system according to claim 2,
The signal line induced by electrostatic coupling or electromagnetic coupling with the signal line, which is arranged in a non-contact and fixed manner near the signal line to be diagnosed with the signal line in a non-contact manner. A circuit board comprising a reactance component for detecting an electric signal corresponding to a signal change of the circuit board.

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