Printed circuit board deterioration detection device

Abstract

To provide a printed circuit board deterioration device and detection method capable of detecting a deterioration state in the case that conductive substances of a cleaning fluid or the like remain within a board to keep the board in the deterioration state.SOLUTION: A plurality of holes 11 without electric conductivity are drilled on a printed circuit board 4 with a circuit pattern formed thereon. A printed circuit board deterioration detection device has groups of conductors 5 undergoing pattern formation on both front and rear surfaces of a printed circuit board 4 to apply voltage to the holes 11, and includes current detection parts 6 for acquiring flowing current information by applying prescribed voltage to the groups of conductors 5, and a deterioration determination part 22 for determining a deterioration in the printed circuit board 4 from a change in the current acquired by the current detection parts 6.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a deterioration detection device for detecting deterioration of a printed circuit board. Place Regarding. [Background technology]

[0002] As an example of a method for inspecting the state of a printed circuit board without removing the board, there is a deterioration detection device disclosed in Patent Document 1. The technology in Patent Document 1 checks the deterioration over time when the printed circuit board is used in an environment that is subject to salt damage or an acidic atmosphere without removing the board. An electrode conductor specifically for inspection is patterned on the printed circuit board, and the deterioration of the printed circuit board is determined by detecting the deterioration of this conductor. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2001-358429 Summary of the Invention [Problem to be solved by the invention]

[0004] However, although the technology of Patent Document 1 was able to detect deterioration over time such as corrosion, it did not address deterioration caused by cleaning, which has been carried out in recent years on air conditioners and the like. When cleaning electrical equipment such as air conditioners, cleaning fluid may remain on printed circuit boards and their connection terminals, which can reduce insulation resistance and cause short circuits or so-called tracking. Therefore, there is a need for printed circuit boards with a function that can detect such insulation deterioration phenomena.

[0005] In view of the above problems, the present invention provides a deterioration detection device for a printed circuit board that can detect when a conductive substance such as a cleaning solution remains in the board and the board is in a deteriorated state. Place It is intended to provide. [Means for solving the problem]

[0006] In order to solve the above problem, the deterioration detection device for a printed circuit board according to the invention of claim 1 is a printed circuit board on which a circuit pattern is formed. On multiple edges that are peripheral to In order to apply a voltage to the holes, the printed circuit board is provided with holes that are not electrically conductive. Along the periphery Patterned connected to the hole A pair of conductors is provided. Chiichi The conductors formed on the other side of the printed circuit board are The conductor on the other side is formed of a single continuous conductor, and the conductor on the other side is separated and allows voltage to be applied independently. A set of conductors is exchange The device has a current information acquisition unit that applies a voltage and acquires information about the current that flows, and a deterioration determination unit that determines the deterioration of the printed circuit board from the change in the current acquired by the current information acquisition unit. The deterioration determination unit detects a change in capacitance from a change in the AC current value acquired by the current information acquisition unit, and determines deterioration of the printed circuit board from the change in capacitance. It is characterized by: With this configuration, if the resistance between conductors connected through electrically non-conductive holes in the printed circuit board changes, i.e., if it decreases, it can be detected from the change in current. Therefore, if deterioration occurs due to the intrusion of air conditioner cleaning fluid or water into the printed circuit board, it can be detected. This can also be useful for preventing tracking. Furthermore, if the resistance of a specific conductor among the multiple conductors changes, an appropriate response can be taken, such as outputting an emergency stop signal.

[0008] In addition, Because an AC voltage is applied to the hole, the change in capacitance can be detected from the change in current even if the resistance value does not change. Therefore, even if a non-conductive foreign object enters the hole, it can be detected from the change in capacitance, and any foreign object that enters the hole can be determined to be a sign of substrate deterioration.

[0009] Claim 2The invention of the present invention is characterized in that at least one electrically non-conductive hole is drilled in a printed circuit board on which a circuit pattern is formed, and that a set of conductors is patterned on both the front and back sides of the printed circuit board to apply a voltage to the hole, and that the invention has a current information acquisition unit that applies a predetermined voltage to the set of conductors and acquires information on the current flowing, and a deterioration determination unit that determines deterioration of the printed circuit board from changes in the current acquired by the current information acquisition unit, wherein the voltage applied to the hole is a DC voltage, the current information acquisition unit acquires DC current information, and the deterioration determination unit determines deterioration of the printed circuit board from changes in the acquired DC current value. With this configuration, if the resistance between conductors connected through electrically non-conductive holes in the printed circuit board changes, i.e., if it decreases, it can be detected from the change in current. Therefore, if deterioration occurs due to the intrusion of air conditioner cleaning fluid or water into the printed circuit board, it can be detected. This can also be useful for preventing tracking. In addition, since detection is performed by applying a DC voltage to the hole, the DC power source supplied to the printed circuit board can be used, and deterioration of the board can be detected with a simple circuit.

[0010] Claim 3 The invention is 2 In the configuration described above, the printed circuit board has a plurality of sets of conductors formed on both the front and back sides, has a power cut-off means for cutting off the power supply to the printed circuit board, and has a cut-off signal generation unit for cutting off the power cut-off means when the number of sets of conductors determined by the degradation determination unit to have deteriorated reaches a predetermined number. According to this configuration, if deterioration occurs in multiple locations on the printed circuit board, that is, if the printed circuit board deteriorates over a wide area, the power supply to the printed circuit board is cut off, thereby reliably preventing the occurrence of tracking and the like.

[0011] Claim 4 The invention is 2In the configuration described above, the printed circuit board has a plurality of sets of conductors formed on both the front and back sides, a power cut-off means for cutting off the power supply to the printed circuit board, and a cut-off signal generation unit for cutting off the power cut-off means when the deterioration determination unit determines that deterioration has occurred in a specific set of conductors. With this configuration, if a part of the printed circuit board to which a high voltage is applied deteriorates, the power supply can be quickly cut off even if other parts are normal, thereby reliably preventing accidents caused by deterioration. [Effects of the Invention]

[0012] According to the present invention, if a hole formed in a printed circuit board that has no electrical conductivity but high insulation resistance decreases in insulation resistance or even becomes conductive, this can be detected from a change in electrical characteristics. Therefore, if deterioration occurs due to the intrusion of air conditioner cleaning fluid or water into the printed circuit board, this can be detected from a change in the electrical characteristics of the hole, which can ultimately be used to prevent tracking from occurring. [Brief explanation of the drawings]

[0013] [Figure 1] FIG. 1 is an explanatory diagram of a deterioration detection device for a printed circuit board. [Figure 2] FIG. 1 is a perspective view of a printed circuit board having a structure for detecting deterioration. [Figure 3] FIG. 3 is a perspective view of the rear side of the printed circuit board of FIG. 2. [Figure 4] FIG. 10 is a cross-sectional view of a printed circuit board showing a structure for detecting deterioration. [Figure 5] FIG. 2 is an explanatory diagram of a current information acquisition unit and a deterioration determination unit. [Figure 6] FIG. 10 is a circuit diagram showing another embodiment of the deterioration detection device. DETAILED DESCRIPTION OF THE INVENTION

[0014] Hereinafter, embodiments embodying the present invention will be described in detail with reference to the drawings. Fig. 1 is an explanatory diagram showing an example of a deterioration detection device for a printed circuit board according to the present invention. The deterioration detection device has a detection circuit unit 1 formed on the printed circuit board to detect deterioration, a measurement and determination unit 2 that measures the current flowing through the detection circuit unit 1 and determines deterioration, and an output unit 3 that outputs the determination result.

[0015] 2 and 3 show a printed circuit board 4 having a detection circuit unit 1, with FIG. 2 being a perspective view of the front side and FIG. 3 being a perspective view of the back side. The detection circuit section 1 is composed of a conductor 5 patterned along the edge of the printed circuit board 4 and a hole 11 formed in the printed circuit board 4. The elements that should be mounted are then placed inside the conductor 5, forming a circuit.

[0016] The conductors 5 start from terminals 13 provided on connector connection parts 12 provided at the end of the printed circuit board 4, and different conductors 5 are arranged on each side so as to connect holes 11 drilled at appropriate positions in the corners of the printed circuit board 4. In this way, the conductors 5 on the surface are arranged in three parts. On the other hand, the conductor 5 patterned on the back surface connects all of the holes 11 with a single conductor 5 that starts from a terminal 13 provided on the connector connection section 12. The conductors 5 are connected to the same hole 11 from both the front and back sides, and the detection circuit section 1 has three sets of conductors 5.

[0017] The detection circuit section 1 thus formed is connected to a power supply and current detection section 6 via a connector connection section 12, and a voltage is applied to each set of conductors 5, and the current is measured or detected. The holes may be formed on all four sides of the printed circuit board 4 or in the center of the board.

[0018] 4 is a cross-sectional explanatory diagram of the detection circuit unit 1, showing the structure of the holes 11 formed in multiple locations. Each hole 11 has ring-shaped conductive parts 11a formed on both the front and back sides, and there is no conductor inside, so there is no electrical conductivity. A conductor 5 is connected to the conductive portion 11a so that a voltage can be applied thereto. Note that Fig. 4 shows a state in which liquid A such as a cleaning liquid remains in some of the holes 11.

[0019] The measurement and judgment unit 2 includes a measurement unit 21 that measures the current flowing in the detection circuit unit 1, a deterioration judgment unit 22 that judges the deterioration of the printed circuit board 4 based on the measured current information, a cut-off signal generation unit 23 that generates a cut-off signal, and a power supply unit 24 that applies a constant voltage to each conductor 5 and supplies power to each conductor 5. The measuring unit 21 obtains current information from the current detecting unit 6 provided for each conductor 5 , converts the information into digital data, and outputs the digital data to the deterioration determining unit 22 .

[0020] The deterioration determination unit 22 is configured with a microcomputer, and compares the current information of each conductor 5 with a preset threshold, and if there is even one conductor 5 through which a current exceeding the threshold flows, it outputs an abnormality occurrence signal to the output unit 3. Furthermore, if there are two or more conductors 5 through which the threshold has been exceeded, it causes the shutdown signal generation unit 23 to output an emergency stop signal.

[0021] The output of the tripping signal generating unit 23 is connected to the circuit breaker 7 that supplies power to the printed circuit board 4, and receives the emergency stop signal to cause the circuit breaker 7 to perform a tripping operation. The output unit 3 also includes an alarm sound unit, an LED for light notification, and the like, and emits an alarm sound and lights up upon receiving an abnormality occurrence signal from the deterioration determination unit 22. The current detection unit 6 and the measurement unit 21 constitute a current information acquisition unit.

[0022] 5 shows the configuration of the power supply unit 24 and measurement unit 21 of the measurement and determination unit 2. The power supply unit 24 is an AC power supply, and an AC voltage is applied to the detection circuit unit 1. That is, it is applied to the hole 11 via the conductor 5. The current that flows in this way is measured by the current detection unit 6, and is determined by the deterioration determination unit 22 via the measurement unit 21. Since the current measured at this time is an AC current, the deterioration determination unit 22 detects the change in capacitance of the hole 11 based on the current change information, and if the change exceeds a certain value, it determines that deterioration has occurred in the printed circuit board 4.

[0023] The deterioration detection device configured as described above operates as follows. First, when there is no foreign object in hole 11, hole 11 is non-conductive, so the resistance value of hole 11 is large and the current flowing through conductor 5 is small. In this state, deterioration determination unit 22 does not detect an abnormality. Because an AC voltage is applied to conductor 5, the impedance is a finite value due to the electrostatic capacitance of hole 11, so the current is not zero but a constant AC current flows.

[0024] From this state, if a conductive liquid such as a cleaning liquid or non-conductive impurities enters any of the holes 11, the capacitance changes, causing the impedance to change (decrease). As a result, the current increases, which is detected by the deterioration determination unit 22. In this way, if the current value of any one of the multiple conductors 5 exceeds the threshold, it is determined that deterioration has occurred and an abnormality occurrence signal is output. This abnormality occurrence signal causes the output unit 3 to issue an alarm, the alarm sound unit sounds an alarm, and the LED lights up.

[0025] Then, if the deterioration progresses further and two or more conductors 5 showing an abnormal current value are detected, an emergency stop signal is output in addition to the abnormality occurrence signal. This emergency stop signal is output to the tripping signal generation unit 23, which outputs a tripping signal to the circuit breaker 7 connected by a signal line, causing the circuit breaker 7 to perform a tripping operation. This circuit breaker 7 supplies power to the printed circuit board 4 on which the detection circuit unit 1 is assembled, and power to this printed circuit board 4 is cut off.

[0026] Incidentally, power to related loads may be shut off simultaneously with this power cutoff. Also, if two or more conductors 5 are detected to exhibit an abnormal current value, an emergency stop signal is output in addition to an abnormality signal, but if there are four or more conductors 5, the decision to output an emergency stop signal may be extended to three or more conductors. Furthermore, if the current value of a conductor 5 in a specific portion of the printed circuit board 4 (for example, a high-voltage portion) exhibits an abnormality, an emergency stop signal may be output immediately.

[0027] In this way, if there is a change, i.e., a decrease, in the insulation resistance between the conductors 5 connected via the electrically non-conductive holes 11 formed in the printed circuit board 4, this can be detected from a change in the current. Therefore, if deterioration occurs due to the intrusion of cleaning fluid or water from an air conditioner into the printed circuit board, this can be detected. This can also be useful in preventing tracking from occurring. Furthermore, because an AC voltage is applied to the hole 11, a change in capacitance can be detected from a change in current even if there is no significant change in resistance. Therefore, even if a non-conductive foreign object enters the hole, it can be detected from a change in capacitance, and any foreign object entering the hole can also be determined to be a sign of substrate deterioration. Furthermore, if deterioration occurs in multiple locations on the printed circuit board 4, that is, if the printed circuit board 4 deteriorates over a wide area, the power supply to the printed circuit board is cut off, thereby reliably preventing the occurrence of tracking and the like.

[0028] Figure 6 shows another example of a deterioration detection device, in which the power source that supplies electricity to the detection circuit unit 1 is a DC power source 18a, and shows the configuration of the measurement and judgment unit 2 that detects deterioration from changes in the resistance value of the conductor 5 (5a to 5d) having a hole 11. The first conductors 5a to third conductors 5c are formed on the periphery of the printed circuit board 4 as in the above embodiment, but the fourth conductor 5d is formed, for example, near a high-voltage charging section of the printed circuit board 4. Reference numeral 14 denotes a set of photocouplers which correspond to the measuring section 21. A photocoupler is provided for each set of conductors 5, and is configured to detect when the resistance value drops and the circuit enters a conducting state.

[0029] Reference numeral 15 denotes a first deterioration determination unit having an LED 20 as an output unit 3 that emits light when deterioration is detected. Reference numeral 16 denotes a second deterioration determination unit that is made up of a logic circuit and outputs an emergency stop signal. The first deterioration determination unit 15 and the second deterioration determination unit 16 constitute a deterioration determination unit 22. Additionally, reference numeral 17 denotes an output element that outputs a tripping signal, and constitutes the tripping signal generating unit 23. This output element 17 is formed of, for example, a photoMOS relay, and when turned on, the circuit breaker 7 performs a tripping operation. Reference numeral 18b denotes a power supply that drives the photocoupler set 14, the first deterioration determining unit 15, and the second deterioration determining unit 16, and reference numeral 18c denotes a power supply that causes the circuit breaker 7 to perform an interruption operation.

[0030] By configuring the measurement and determination unit 2 in this manner, if any of the first conductor 5a to the third conductor 5c indicates an abnormal value, the LED 20 lights up and an alarm is issued. Furthermore, if all three conductors 5, the first conductor 5a to the third conductor 5c, indicate abnormal values ​​simultaneously, or if the current in the fourth conductor 5d indicates an abnormal value, the second deterioration determination unit 16 outputs a signal and the circuit breaker 7 performs an interruption operation. Therefore, if a liquid such as a cleaning liquid gets into the formed holes 11 and is not removed, the insulating function will be reduced or the hole will become conductive, causing a current to flow and thus degradation of the substrate will be detected.

[0031] In this way, since detection is performed by applying a DC voltage to the hole 11, the DC power source supplied to the printed circuit board 4 can be used, and deterioration of the board can be detected with a simple circuit. Furthermore, if deterioration occurs in multiple locations on the printed circuit board 4, that is, if the printed circuit board 4 deteriorates over a wide area, the power supply to the printed circuit board 4 is cut off, thereby reliably preventing the occurrence of tracking and the like. Furthermore, if a portion of the printed circuit board 4 to which a high voltage is applied deteriorates, the power supply is quickly shut off even if other portions are normal, so accidents due to deterioration can be reliably prevented.

[0032] In the above embodiment, the explanation is based on the assumption that a liquid such as a cleaning solution is attached, but this is shown assuming the cleaning of an air conditioner, etc., and the deterioration detection device of the present invention can detect deterioration from changes in the electrical characteristics even when a solid substance is attached or the device is filled with gas. [Explanation of symbols]

[0033] 1··Detection circuit section, 2··Measurement and judgment section, 3··Output section, 4··Printed circuit board, 5··Conductor, 6··Current detection section (current information acquisition section), 7··Circuit breaker (power supply interruption means), 11··Hole, 18a··DC power supply, 21··Measurement section (current information acquisition section), 22··Deterioration judgment section, 24··Power supply section.

Claims

1. a printed circuit board on which a circuit pattern is formed, the printed circuit board having a plurality of peripheral sides on which electrically non-conductive holes are formed, and a set of conductors patterned along the peripheral parts on both the front and back sides of the printed circuit board and connected to the holes in order to apply a voltage to the holes; The conductors formed on one surface of the set of conductors are separated for each side of the printed circuit board, allowing voltage to be applied independently; the conductor on the other surface is formed of a single continuous conductor, a current information acquiring unit that applies a predetermined AC voltage to the set of conductors and acquires information about the current that flows; a deterioration determination unit that determines deterioration of the printed circuit board from a change in current acquired by the current information acquisition unit; The deterioration determination unit detects a change in capacitance from a change in the AC current value acquired by the current information acquisition unit, and determines the deterioration of the printed circuit board from the change in capacitance.

2. A printed circuit board on which a circuit pattern is formed, has at least one electrically non-conductive hole drilled therein, and has a set of conductors patterned on both the front and back surfaces of the printed circuit board for applying a voltage to the hole; a current information acquiring unit that applies a predetermined voltage to the pair of conductors and acquires information about a current that flows; a deterioration determination unit that determines deterioration of the printed circuit board from a change in current acquired by the current information acquisition unit; the voltage applied to the hole is a DC voltage, and the current information acquiring unit acquires DC current information; The deterioration determination unit determines the deterioration of the printed circuit board from a change in the obtained DC current value.

3. A printed circuit board having a plurality of sets of conductors formed on both the front and back surfaces, and having a power cut-off means for cutting off the power supply to the printed circuit board, 3. The printed circuit board deterioration detection device according to claim 2, further comprising a shut-off signal generating unit that shuts off the power supply shut-off means when the number of sets of conductors determined by the deterioration determination unit to have deteriorated reaches a predetermined number.

4. The printed circuit board has a plurality of sets of conductors formed on both the front and back sides, and has a power cut-off means for cutting off the power supply to the printed circuit board, 3. The printed circuit board deterioration detection device according to claim 2, further comprising a cutoff signal generating section that cuts off the power supply cutoff means when the deterioration determining section determines that deterioration has occurred in a specific set of conductors.

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