Inspection method and inspection system

Abstract

The present application provides an inspection method and an inspection system. The inspection method is used for inspecting a printed wiring board having a first wiring as a transmission characteristic inspection object and a second wiring adjacent to the first wiring and not as a transmission characteristic inspection object, the inspection method comprising: measuring a transmission characteristic of the first wiring by a vector network analyzer; measuring a direct current resistance of the second wiring by a direct current resistance meter; inspecting a transmission characteristic of the first wiring based on the transmission characteristic of the first wiring, and inspecting an open circuit state and a short circuit state of the first wiring; and inspecting an open circuit state of the second wiring based on the direct current resistance of the second wiring.

Description

Technical Field

[0001] This invention relates to inspection methods and systems. More specifically, one aspect of the invention relates to an inspection method and system for inspecting printed wiring boards, including wiring such as high-speed transmission lines, which are the objects of transmission characteristic inspection. Background Technology

[0002] In recent years, with the miniaturization and high-speed development of electronic devices such as smartphones, laptops, digital cameras, and game consoles, the amount of information processed has increased dramatically. Therefore, signal speeds are trending towards increasingly higher speeds. Furthermore, since 2019, portable communication terminals such as smartphones have begun to transition to the next-generation communication standard, 5G. In 5G, the frequency of signals transmitted and received by communication terminals has changed from several GHz to 20-30 GHz. Moreover, it is expected that the signal frequency will increase to around 50 GHz around 2022.

[0003] Due to the increasing speed of signals, the signal lines (high-speed transmission lines) of printed circuit boards (PCBs) are required to meet specifications related to transmission characteristics. For example, to suppress signal reflections, characteristic impedance and voltage standing wave ratio (VSWR) are sometimes specified in the specifications. Furthermore, since transmission loss tends to increase with higher signal frequencies, the transmission loss of the line is sometimes specified in the specifications. Additionally, when multiple signal lines are arranged on the same PCB, the interference (crosstalk / isolation) between adjacent signal lines is sometimes specified in the specifications. To confirm compliance with the specifications related to transmission characteristics, the transmission characteristics are measured during the inspection of PCBs with high-speed transmission lines to determine their suitability.

[0004] Furthermore, Japanese Patent Publication No. 2019-106508 discloses a printed wiring board for high-speed signal transmission in electronic devices. In this printed wiring board, signal lines and grounding lines are disposed within an insulating substrate made of a liquid crystal polymer or similar material. The signal lines are configured as high-speed transmission lines in stripline form.

[0005] As described above, a transmission characteristic check is performed on a printed circuit board with high-speed transmission lines. This transmission characteristic check is performed using a vector network analyzer.

[0006] In addition to transmission characteristics, open / short circuit checks are performed to check for broken high-speed transmission lines and short circuits between adjacent wiring. A DC resistance meter is used for these checks.

[0007] Previously, high-speed transmission lines on printed circuit boards were checked for transmission characteristics and open / short circuits separately. This resulted in longer inspection times and increased inspection costs. Summary of the Invention

[0008] Therefore, the object of the present invention is to provide an inspection method and inspection system that can improve the inspection efficiency of printed wiring boards with high-speed transmission lines.

[0009] This invention provides an inspection method.

[0010] A method for inspecting a printed wiring board, the printed wiring board having a first wiring that is the object of transmission characteristic inspection and a second wiring adjacent to the first wiring that is not the object of transmission characteristic inspection, the inspection method comprising:

[0011] The transmission characteristics of the first cabling were measured using a vector network analyzer;

[0012] The DC resistance of the second wiring is measured using a DC resistance meter;

[0013] Based on the transmission characteristics of the first wiring, check the transmission characteristics of the first wiring, and check the open circuit and short circuit states of the first wiring; and

[0014] Based on the DC resistance of the second wiring, check the open circuit status of the second wiring.

[0015] Furthermore, in the aforementioned inspection method,

[0016] Measuring the transmission characteristics of the first cabling may include measuring the reflection characteristics of the first cabling using the vector network analyzer as the transmission characteristics.

[0017] Checking the open-circuit and short-circuit states of the first wiring includes: determining the first wiring to be in a short-circuit state when the characteristic impedance obtained by performing TDR transformation on the reflection characteristics of the first wiring is lower than a specified short-circuit judgment threshold; and determining the first wiring to be in an open-circuit state when the characteristic impedance exceeds the specified open-circuit judgment threshold.

[0018] Furthermore, in the aforementioned inspection method,

[0019] Measuring the transmission characteristics of the first cabling may include measuring the transmission loss of the first cabling using the vector network analyzer as the transmission characteristic.

[0020] Checking the open-circuit and short-circuit states of the first wiring includes: determining that the first wiring is in a short-circuit state when the transmission loss of the first wiring is lower than a predetermined short-circuit judgment threshold at at least one frequency; and determining that the first wiring is in an open-circuit state when the transmission loss exceeds the predetermined open-circuit judgment threshold.

[0021] Alternatively, the inspection method may include not performing a short-circuit check on the second wiring based on the DC resistance meter.

[0022] Furthermore, in the aforementioned inspection method,

[0023] The first wiring could be a high-speed transmission line, and the second wiring could be a power supply line, a grounding line, or a low-speed transmission line.

[0024] Furthermore, in the aforementioned inspection method,

[0025] The printed wiring board may also have a third wiring adjacent to the first wiring and serving as the object of transmission characteristic inspection.

[0026] The inspection method also includes:

[0027] The transmission characteristics of the third cabling are measured using the vector network analyzer; and

[0028] Based on the transmission characteristics of the third wiring, the transmission characteristics of the third wiring are checked, and the open circuit state and short circuit state of the third wiring are checked.

[0029] Furthermore, in the aforementioned inspection method,

[0030] The printed wiring board may also have a fourth wiring adjacent to the second wiring and serving as the object of transmission characteristic inspection.

[0031] The inspection method also includes:

[0032] The transmission characteristics of the fourth cabling are measured using the vector network analyzer; and

[0033] Based on the transmission characteristics of the fourth wiring, check the transmission characteristics of the fourth wiring, and check the open circuit state and short circuit state of the fourth wiring.

[0034] Furthermore, in the aforementioned inspection method,

[0035] The printed wiring board may also have a fifth wiring adjacent to the second wiring, which is not the object of transmission characteristic inspection.

[0036] The inspection method also includes:

[0037] The DC resistance of the fifth wiring is measured using the DC resistance meter; and

[0038] Based on the DC resistance of the fifth wiring, check the open circuit status of the fifth wiring.

[0039] Furthermore, in the aforementioned inspection method,

[0040] The printed wiring board may be a flexible printed wiring board equipped with a first connector and a second connector, wherein the first connector is electrically connected to the input terminal of the first wiring and the input terminal of the second wiring, and the second connector is electrically connected to the output terminal of the first wiring and the output terminal of the second wiring.

[0041] Furthermore, in the aforementioned inspection method,

[0042] The printed wiring board may be a flexible printed wiring board without an installed connector, which is included in the workpiece along with other printed wiring boards.

[0043] The present invention also provides an inspection system.

[0044] For inspecting printed wiring boards, the printed wiring boards having a first wiring that is the object of transmission characteristic inspection and a second wiring adjacent to the first wiring that is not the object of transmission characteristic inspection, the inspection system comprising:

[0045] A vector network analyzer has a first measurement port electrically connected to one end of the first wiring and a second measurement port electrically connected to the other end of the first wiring, for measuring the transmission characteristics of the first wiring;

[0046] A DC resistance meter has a first measurement port electrically connected to one end of the second wiring and a second measurement port electrically connected to the other end of the second wiring, for measuring the DC resistance of the second wiring; and

[0047] The information processing device is connected to the vector network analyzer and the DC resistance meter to enable communication.

[0048] The information processing device checks the transmission characteristics of the first cabling based on the transmission characteristics measured by the vector network analyzer, and checks the open-circuit and short-circuit states of the first cabling.

[0049] The information processing device checks the open circuit status of the second wiring based on the DC resistance of the second wiring measured by the DC resistance meter.

[0050] Furthermore, the inspection system may include:

[0051] A first inspection tool, comprising a first inspection probe electrically connected to the first measurement port of the vector network analyzer and a second inspection probe electrically connected to the first measurement port of the DC resistance meter; and

[0052] The second inspection tool has a first inspection probe electrically connected to the second measurement port of the vector network analyzer and a second inspection probe electrically connected to the second measurement port of the DC resistance meter.

[0053] The first inspection probe of the first inspection tool is configured to be electrically connected to one end of the first wiring, and the second inspection probe of the first inspection tool is configured to be electrically connected to one end of the second wiring.

[0054] The first inspection probe of the second inspection tool is configured to be electrically connected to the other end of the first wiring, and the second inspection probe of the second inspection tool is configured to be electrically connected to the other end of the second wiring.

[0055] Furthermore, in the inspection system,

[0056] The first and second inspection probes of the first inspection tool may be configured to be mounted on the connector terminals of the first connector mounted on the printed wiring board.

[0057] The first and second inspection probes of the second inspection tool are configured to be mounted on the connector terminals of the second connector mounted on the printed wiring board.

[0058] Furthermore, in the inspection system,

[0059] The inspection system may inspect not only the printed wiring board, but also printed wiring boards that are different from the printed wiring board.

[0060] The different printed wiring boards have a third wiring that serves as the object of transmission characteristic inspection.

[0061] The vector network analyzer also has a third measurement port electrically connected to one end of the third wiring on the different printed wiring board and a fourth measurement port electrically connected to the other end of the third wiring, for measuring the transmission characteristics of the third wiring.

[0062] The present invention also provides an inspection method.

[0063] The inspection method for inspecting a printed wiring board having wiring that is the object of transmission characteristic inspection includes:

[0064] The transmission characteristics of the cabling were measured using a vector network analyzer; and

[0065] Based on the transmission characteristics of the wiring, check the transmission characteristics of the wiring, and check the open circuit state and short circuit state of the wiring.

[0066] According to the present invention, an inspection method and inspection system are provided that can improve the inspection efficiency of printed wiring boards with high-speed transmission lines. Attached Figure Description

[0067] Figure 1 This is a diagram showing the general structure of the inspection system according to the first embodiment.

[0068] Figure 2A This is a diagram illustrating an example of characteristic impedance (normal and short-circuit states) based on reflection characteristics measured by a vector network analyzer.

[0069] Figure 2B This is a diagram illustrating an example of characteristic impedance (normal and open-circuit states) based on reflection characteristics measured by a vector network analyzer.

[0070] Figure 2C This is a diagram illustrating an example of transmission loss (normal and short-circuit states) measured by a vector network analyzer.

[0071] Figure 2D This is a diagram illustrating an example of transmission loss (normal and open-circuit states) measured by a vector network analyzer.

[0072] Figure 3 This is a flowchart illustrating the inspection method for implementing the method.

[0073] Figure 4 This is a flowchart illustrating the details of the inspection method used in the implementation of the method.

[0074] Figure 5A This is another example of a printed wiring board that is being inspected.

[0075] Figure 5B This is another example of a printed wiring board that is being inspected.

[0076] Figure 6 This is a diagram showing the general structure of the inspection system according to the second embodiment.

[0077] Figure 7 This is a flowchart illustrating a comparative example of a printed wiring board manufacturing method, including an inspection process for the printed wiring board.

[0078] Figure 8 This is a top view showing an example of a piece of work comprising multiple printed wiring boards.

[0079] Figure 9A yes Figure 8 The top view of the printed wiring board of the product sheet shown.

[0080] Figure 9B It is along Figure 9AA sectional view along line II.

[0081] Figure 10 This is a diagram used to illustrate the open / short circuit check based on a DC resistance meter for comparative examples.

[0082] Figure 11A This is a top view of a printed wiring board mounted as a component of a printed wiring board with connectors.

[0083] Figure 11B It is along Figure 11A A sectional view along line II-II.

[0084] Figure 12 This is a diagram used to illustrate the open / short circuit check based on a DC resistance meter for comparative examples.

[0085] Figure 13 This is a diagram used to illustrate the transmission characteristic check based on a vector network analyzer for comparative examples.

[0086] Explanation of reference numerals in the attached figures

[0087] 1. 1A Inspection System

[0088] 2 Vector Network Analyzer

[0089] Measurement ports 21, 22, 23, and 24

[0090] 3. DC Resistance Meter

[0091] Measurement ports 31 and 32

[0092] 4. Information processing device

[0093] 5 and 6 Inspection tools

[0094] 51, 52, 53, 61, 62, 63 Check probes

[0095] 54, 55, 64, 65 coaxial cables

[0096] 55 and 65 cables

[0097] 100, 100A, 100B, 100C Component Mounting FPC

[0098] 110, 110A, 110B Printed Wiring Boards

[0099] Wiring 111, 112, 113

[0100] 111a, 112a, 113a Input terminals

[0101] 111b, 112b, 113b Output terminals

[0102] 119 Insulating substrate

[0103] 120, 130 connectors

[0104] Connector terminals 121, 122, 123, 131, 132, 133

[0105] 500 DC Resistance Meter

[0106] 510, 520 measurement ports

[0107] 530, 540 Inspection Tools

[0108] 550, 560 cables

[0109] 600 Vector Network Analyzer

[0110] 610, 620, 630, 640 measurement ports

[0111] P1, P2 contacts

[0112] S product sheet Detailed Implementation

[0113] Before describing the embodiments of the present invention, comparative examples will be described.

[0114] <Comparative Example>

[0115] Before describing the implementation method, according to Figure 7 The flowchart illustrates a comparative example of a printed wiring board manufacturing method, including a printed wiring board inspection process.

[0116] First, an article sheet comprising multiple flexible printed wiring boards (FPCs) is manufactured (step S101). Figure 8 It is a top view of a piece S comprising multiple printed wiring boards 110. Figure 8 The dashed lines in the diagram represent the outline of the product. In this example, twelve printed wiring boards 110 are formed in the product sheet S.

[0117] like Figure 9A As shown, each printed wiring board 110 of the product sheet S has multiple wirings, including wiring 111 (first wiring), wiring 112 (second wiring), and wiring 113 (third wiring). Wiring 111 and wiring 113 are wirings that are subject to transmission characteristic testing, such as high-speed transmission lines used for transmitting high-speed signals. Wiring 112 is a wiring that is not subject to transmission characteristic testing, such as a grounding wiring. The grounding wiring is a wiring electrically connected to the ground plane (not shown) on the outer layer of the printed wiring board 110. Alternatively, wiring 112 can also be a power supply line used for transmitting power or a low-speed transmission line for which transmission characteristic testing is not required.

[0118] like Figure 9B As shown, wirings 111, 112, and 113 are formed in an insulating substrate 119. Wirings 111, 112, and 113 have lines and interlayer connection members such as vias or through-holes formed in the inner layer of the printed wiring board 110. Input terminals 111a, 112a, and 113a and output terminals 111b, 112b, and 113b are formed on the surface of the insulating substrate 119. Wiring 111 electrically connects input terminal 111a and output terminal 111b. Wiring 112 electrically connects input terminal 112a and output terminal 112b. Wiring 113 electrically connects input terminal 113a and output terminal 113b. In other words, one end of wiring 111, 112, and 113 is electrically connected to the input terminals 111a, 112a, and 113a of the printed wiring board 110, respectively, and the other end of wiring 111, 112, and 113 is electrically connected to the output terminals 111b, 112b, and 113b, respectively.

[0119] In addition, the wiring to be inspected is not limited to wiring embedded in an insulating substrate, but can also be wiring formed on the surface of an insulating substrate in the form of a micro strip structure.

[0120] Next, an open / short circuit check is performed on each printed wiring board 110 of the finished product S (step S102). Specifically, the wirings 111, 112, and 113 of the printed wiring board 110 are checked to see if they are in an open circuit state (i.e., whether a broken wire has occurred) and if they are in a short circuit state (i.e., whether a short circuit has occurred). This step involves... Figure 10 The inspection structure shown is used. The DC resistance meter 500 has measurement ports 510 and 520 for measuring DC resistance values. Measurement port 510 is electrically connected to contact P1 of the inspection tool 530 via cable 550. Similarly, measurement port 520 is electrically connected to contact P2 of the inspection tool 540 via cable 560.

[0121] The inspection tool 530 has inspection probes 531, 532, and 533. Inspection probe 531 contacts the input terminal 111a of wiring 111. Similarly, inspection probe 532 contacts the input terminal 112a of wiring 112, and inspection probe 533 contacts the input terminal 113a of wiring 113.

[0122] Inspection tool 540 has inspection probes 541, 542, and 543. Inspection probe 541 contacts the output terminal 111b of wiring 111. Similarly, inspection probe 542 contacts the output terminal 112b of wiring 112, and inspection probe 543 contacts the output terminal 113b of wiring 113.

[0123] Inspection tool 530 has a switching mechanism that selectively connects any one of inspection probes 531, 532, and 533 to contact P1. Similarly, inspection tool 540 has a switching mechanism that selectively connects any one of inspection probes 541, 542, and 543 to contact P2. By controlling these switching mechanisms, the DC resistance of each of the traces 111, 112, and 113 on the printed wiring board 110 is measured to check whether each trace is open-circuit. For example, by controlling the switching mechanisms, a state is obtained where contact P1 is electrically connected to inspection probe 531 and contact P2 is electrically connected to inspection probe 541. In this state, the DC resistance is measured by DC resistance meter 500. If the measured DC resistance exceeds a predetermined open-circuit judgment threshold, it is determined that a break has occurred in trace 111. The same check is performed on traces 112 and 113.

[0124] In addition, this step also checks for short circuits between the wirings. For example, by controlling the switching mechanism, a state is obtained where contact P1 and inspection probe 531 are electrically connected, and contact P2 and inspection probe 542 are electrically connected. In this state, the DC resistance is measured by a DC resistance meter 500. If the measured DC resistance is lower than a specified short circuit judgment threshold, it is determined that a short circuit has occurred between wiring 111 and wiring 112. The same checks are performed between wiring 111 and wiring 113, and between wiring 112 and wiring 113.

[0125] Next, perform an appearance inspection of the finished product piece S (step S103).

[0126] Next, connectors 120 and 130 are installed on the printed wiring board 110, which was determined to be normal in the open / short circuit check of step S102 and the visual inspection of step S103 (step S104). Figure 11A and Figure 11B As shown, connector 120 (first connector) has connector terminals 121, 122, and 123. Connector 130 (second connector) has connector terminals 131, 132, and 133.

[0127] Connector 120 is mounted on printed wiring board 110 such that connector terminals 121, 122, and 123 are electrically connected to input terminals 111a, 112a, and 113a, respectively. Similarly, connector 130 is mounted on printed wiring board 110 such that connector terminals 131, 132, and 133 are electrically connected to output terminals 111b, 112b, and 113b, respectively.

[0128] Next, the product sheet S is cut into multiple FPCs (step S105). Specifically, the product sheet S is cut along the outline of the product to create a printed wiring board 110 with connectors 120 and 130 mounted on it. Hereinafter, the flexible printed wiring board with connectors mounted on it will also be referred to as a "component-mounted FPC".

[0129] Next, an open / short circuit check is performed on the printed wiring board 110 (component mounting FPC 100) on which connectors 120 and 130 are mounted (step S106). In this step, the connector terminals of connector 120 and connector 130 are checked to see if they are in an open circuit state or a short circuit state.

[0130] Specifically, such as Figure 12 As shown, using the DC resistance meter 500, the mounting portions of connectors 120 and 130 are checked for short circuits or open circuits due to poor soldering, etc. This check is performed with the inspection probes 531, 532, and 533 of the inspection tool 530 in contact with connector terminals 121, 122, and 123, respectively, and with the inspection probes 541, 542, and 543 of the inspection tool 540 in contact with connector terminals 131, 132, and 133, respectively. Subsequent checks for open circuits and short circuits are the same as in step S102, therefore detailed explanations are omitted.

[0131] Next, the transmission characteristics of the printed wiring board 110 (component mounting FPC 100) with connectors installed are checked (step S107). The transmission characteristics of the wiring to be checked are measured. That is, the transmission characteristics of the wiring 111 and 113, which are high-speed transmission lines, are measured.

[0132] In the inspection of step S107, such as Figure 13 As shown, a vector network analyzer 600 is used. The vector network analyzer 600 has measurement ports 610, 620, 630, and 640. Measurement port 610 is electrically connected to the inspection probe 651 of the inspection tool 650 via a coaxial cable 653. Similarly, measurement port 620 is electrically connected to the inspection probe 661 of the inspection tool 660 via a coaxial cable 663. Measurement port 630 is electrically connected to the inspection probe 652 of the inspection tool 650 via a coaxial cable 654. Measurement port 640 is electrically connected to the inspection probe 662 of the inspection tool 660 via a coaxial cable 664.

[0133] In the inspection of step S107, such as Figure 13As shown, test probe 651 is brought into contact with connector terminal 121, test probe 652 is brought into contact with connector terminal 123, test probe 661 is brought into contact with connector terminal 131, and test probe 662 is brought into contact with connector terminal 133. Subsequently, the transmission characteristics of wiring 111 and wiring 113 are measured using a vector network analyzer 600.

[0134] After the evaluation of transmission characteristics is completed, a visual inspection of the component-mounted FPC100 is performed (step S108). Component-mounted FPC100 that is determined to be free of abnormalities during the visual inspection becomes an article assembled into an electronic device.

[0135] As described above, in the comparative example of the printed circuit board inspection method, it is necessary to perform open / short circuit checks and transmission characteristic checks on the printed circuit board with connectors installed separately. This inevitably leads to a decrease in inspection efficiency. In contrast, in the printed circuit board inspection method of the embodiment of the present invention, as described later, based on the measurement results of a vector network analyzer, not only are the transmission characteristics of the wiring to be inspected for transmission characteristics checked, but also the open / short circuit states of the wiring are checked. Therefore, it is not necessary to perform separate open / short circuit checks on the wiring to be inspected for transmission characteristics. Therefore, inspection efficiency can be significantly improved.

[0136] The embodiments of the present invention will now be described with reference to the accompanying drawings.

[0137] (First Implementation)

[0138] Reference Figure 1 The inspection system of the first embodiment will be described.

[0139] The inspection system 1 in this embodiment is an inspection system for inspecting the component mounting FPC100.

[0140] As described above, the component mounting FPC 100 for the inspection object has a printed wiring board 110 and connectors 120 and 130 mounted on the printed wiring board 110. The printed wiring board 110 has: wiring 111 that is the object of transmission characteristic inspection; wiring 112 that is adjacent to wiring 111 but is not the object of transmission characteristic inspection; and wiring 113 that is adjacent to wiring 111 and is the object of transmission characteristic inspection.

[0141] like Figure 1 As shown, the inspection system 1 of this embodiment includes: a vector network analyzer 2, a DC resistance meter 3, an information processing device 4, an inspection tool (first inspection tool) 5, and an inspection tool (second inspection tool) 6. Alternatively, the inspection system 1 may also include a holding mechanism (not shown) for holding the component mounted on the FPC 100.

[0142] The following is a detailed description of each component of inspection system 1.

[0143] The vector network analyzer 2 measures the transmission characteristics of cabling in the same manner as the vector network analyzer 600. The vector network analyzer 2 of this embodiment has measurement ports 21, 22, 23, and 24 to measure the transmission characteristics of cabling 111 and cabling 113. At least one of reflection characteristics and transmission loss is measured as the transmission characteristics.

[0144] Additionally, crosstalk between cabling 111 and cabling 113 can also be measured as a transmission characteristic. Furthermore, the number of measurement ports of the vector network analyzer 2 is not limited to four; it can also be six or eight, etc.

[0145] The DC resistance meter 3 measures the DC resistance of the wiring in the same manner as the DC resistance meter 500. For example, a multimeter is used as the DC resistance meter 3.

[0146] The DC resistance meter 3 of this embodiment has a measurement port 31 electrically connected to one end (input terminal 112a) of the wiring 112 and a measurement port 32 electrically connected to the other end (output terminal 112b) of the wiring 112, for measuring the DC resistance of the wiring 112. Furthermore, the number of measurement ports of the DC resistance meter 3 is not limited to two; it can also be four or six, etc.

[0147] Inspection tool 5 has: an inspection probe 51 (first inspection probe) electrically connected to the measurement port 21 (first measurement port) of vector network analyzer 2; an inspection probe 52 (second inspection probe) electrically connected to the measurement port 31 (first measurement port) of DC resistance meter 3; and an inspection probe 53 electrically connected to the measurement port 23 (third measurement port) of vector network analyzer 2. Inspection tool 6 has: an inspection probe 61 (first inspection probe) electrically connected to the measurement port 22 (second measurement port) of vector network analyzer 2; an inspection probe 62 (second inspection probe) electrically connected to the measurement port 32 (second measurement port) of DC resistance meter 3; and an inspection probe 63 electrically connected to the measurement port 24 (fourth measurement port) of vector network analyzer 2.

[0148] The inspection probe 51 of the inspection tool 5 is configured to be electrically connected to one end of the wiring 111 (input terminal 111a). The inspection probe 52 is configured to be electrically connected to one end of the wiring 112 (input terminal 112a). The inspection probe 53 is configured to be electrically connected to one end of the wiring 113 (input terminal 113a).

[0149] The inspection probe 61 of the inspection tool 6 is configured to be electrically connected to the other end (output terminal 111b) of the wiring 111. The inspection probe 62 is configured to be electrically connected to the other end (output terminal 112b) of the wiring 112. The inspection probe 63 is configured to be electrically connected to the other end (output terminal 113b) of the wiring 113.

[0150] In this embodiment, the printed wiring board 110 (i.e., component mount FPC 100) on which connectors 120 and 130 are mounted is inspected. Therefore, the inspection probes 51, 52, and 53 of the inspection tool 5 are configured to be mounted on the connector terminals 121, 122, and 123 of the connector 120 mounted on the printed wiring board 110, respectively. Similarly, the inspection probes 61, 62, and 63 of the inspection tool 6 are configured to be mounted on the connector terminals 131, 132, and 133 of the connector 130 mounted on the printed wiring board 110, respectively. For example, when the connector terminal is concave, the inspection probe is inserted into the connector terminal when mounted on the connector terminal.

[0151] The vector network analyzer 2, the DC resistance meter 3, and the component mounting FPC100 of the object under inspection are connected via the aforementioned inspection tools 5 and 6. For example... Figure 1 As shown, measurement port 21 of the vector network analyzer 2 is electrically connected to one end of wiring 111 (input terminal 111a). Measurement port 22 is electrically connected to the other end of wiring 111 (output terminal 111b). Similarly, measurement port 23 is electrically connected to one end of wiring 113 (input terminal 113a). Measurement port 24 is electrically connected to the other end of wiring 113 (output terminal 113b).

[0152] More specifically, measurement port 21 is electrically connected to connector terminal 121 of connector 120 via coaxial cable 54 and inspection probe 51 of inspection tool 5. Measurement port 22 is electrically connected to connector terminal 131 of connector 130 via coaxial cable 64 and inspection probe 61 of inspection tool 6. Similarly, measurement port 23 is electrically connected to connector terminal 123 of connector 120 via coaxial cable 55 and inspection probe 53 of inspection tool 5. Measurement port 24 is electrically connected to connector terminal 133 of connector 130 via coaxial cable 65 and inspection probe 63 of inspection tool 6.

[0153] The measurement port 31 of the DC resistance meter 3 is electrically connected to the connector terminal 122 of the connector 120 via the coaxial cable 55 and the inspection probe 52 of the inspection tool 5. The measurement port 32 is electrically connected to the connector terminal 132 of the connector 130 via the coaxial cable 65 and the inspection probe 62 of the inspection tool 6.

[0154] Next, the information processing device 4 will be described.

[0155] The information processing device 4 is connected to the vector network analyzer 2 and the DC resistance meter 3 via wired or wireless communication in a manner that enables communication with them. The information processing device 4 simultaneously or sequentially sends trigger signals for the start of measurement to the vector network analyzer 2 and the DC resistance meter 3. Furthermore, the information processing device 4 receives measurement results from the vector network analyzer 2 and the DC resistance meter 3.

[0156] The information processing device 4 is configured to determine whether the component installation FPC100 is normal based on the measurement results received from the vector network analyzer 2 and the DC resistance meter 3. The information processing device 4 is, for example, a personal computer. The information processing device 4 can also be a portable information terminal such as a tablet terminal or a smartphone.

[0157] The processing content of the information processing device 4 will be further explained in detail.

[0158] Information processing device 4 checks the transmission characteristics of cabling 111 based on the transmission characteristics measured by vector network analyzer 2, and checks for open-circuit and short-circuit states of cabling 111. Similarly, information processing device 4 checks the transmission characteristics of cabling 113 based on its transmission characteristics, and checks for open-circuit and short-circuit states of cabling 113. Afterwards, information processing device 4 displays the check results on a display.

[0159] First, the inspection of transmission characteristics will be explained. The information processing device 4 inspects the transmission characteristics of the cabling 111, for example, based on the characteristic impedance obtained by performing a TDR transformation on the reflection characteristics measured by the vector network analyzer 2. For example, in the time region (cabling region) corresponding to the area where the cabling 111 is formed, if the characteristic impedance is within a specified range (e.g., within 50 ± 5 Ω), the information processing device 4 determines that the transmission characteristics of the cabling are normal.

[0160] In addition, TDR transformation is usually performed by the vector network analyzer 2. However, it is not limited to this; the information processing device 4 can also perform TDR transformation.

[0161] In addition, the information processing device 4 can also check the transmission characteristics of the cabling based on the voltage standing wave ratio (VSWR) obtained by performing TDR transformation on the measured reflection characteristics.

[0162] In addition, the information processing device 4 can also determine whether the transmission characteristics of the cabling 111 are good based on the transmission loss or crosstalk of the cabling 111 measured by the vector network analyzer 2, according to the inspection specifications.

[0163] Next, the open / short circuit check based on transmission characteristics will be explained. If the characteristic impedance obtained by performing TDR transformation on the reflection characteristics of wiring 111 is lower than the predetermined short circuit judgment threshold, the information processing device 4 determines that wiring 111 is in a short circuit state. On the other hand, if the characteristic impedance exceeds the predetermined open circuit judgment threshold, the information processing device 4 determines that wiring 111 is in an open circuit state.

[0164] Reference Figure 2A and Figure 2B This section provides a detailed explanation of the open / short circuit check. Figure 2A An example of characteristic impedance under normal and short-circuit conditions. Figure 2B An example of characteristic impedance under normal and open-circuit conditions.

[0165] Under normal conditions where no open circuit or short circuit has occurred, such as Figure 2A and Figure 2B As shown by the solid line in the waveform, peaks appear at the times corresponding to the positions of the front ends of test probes 51 and 61, respectively. The characteristic impedance between the peaks is approximately equal to the design value (50Ω) used for impedance matching.

[0166] In the event of a short circuit in connector 120 (e.g., when connector terminals 121 and 122 are electrically connected due to excessive solder), such as Figure 2A As shown by the dashed line waveform, the characteristic impedance decreases sharply from the time corresponding to the position of connector 120, and takes a low value throughout the wiring area. Therefore, if the characteristic impedance in the wiring area is lower than the specified short-circuit judgment threshold, the information processing device 4 can determine that wiring 111 is in a short-circuit state. The short-circuit judgment threshold is... Figure 2A In some cases, a value of 35Ω to 45Ω can be used. Alternatively, the lower limit of the characteristic impedance threshold (e.g., 45Ω) can be used as the short-circuit threshold.

[0167] In the event of a wire breakage in connector 120 (e.g., in the case where the input terminal 111a and connector terminal 121 are not electrically connected due to insufficient solder), such as Figure 2B As shown by the dashed line, the characteristic impedance increases sharply and diverges from the time corresponding to the position of connector 120. Therefore, if the characteristic impedance exceeds the predetermined open-circuit detection threshold in the wiring area, the information processing device 4 can determine that wiring 111 is in an open-circuit state. The open-circuit detection threshold is... Figure 2B In some cases, values ​​above 65Ω are used.

[0168] As described above, the information processing device 4 uses the characteristic impedance obtained from the reflection characteristics measured by the vector network analyzer 2 to perform open / short circuit checks on the wiring 111. Furthermore, the information processing device 4 also checks the transmission characteristics of the wiring 113 in the same manner as for the wiring 111, based on the reflection characteristics of the wiring 113, and performs open / short circuit checks on the wiring 113.

[0169] The information processing device 4 is not limited to using reflection characteristics; it can also use other transmission characteristics (transmission loss, VSWR) measured by the vector network analyzer 2 to perform open / short circuit checks on cabling 111 and 113. Here, refer to... Figure 2C and Figure 2D Explain the use of transmission loss. Figure 2C This is an example of transmission loss under normal and short-circuit conditions. Figure 2D This is an example of transmission loss under normal and open-circuit conditions.

[0170] In the event of a short circuit in connector 120, such as Figure 2C As shown by the dashed line, the waveform of transmission loss is completely different from the normal waveform, and the transmission loss decreases sharply at specific frequencies (approximately 3GHz, 6.5GHz, etc.). Therefore, when the transmission loss is below the short-circuit detection threshold at a specified frequency, the information processing device 4 can determine that wiring 111 is in a short-circuit state. The short-circuit detection threshold is... Figure 2C For example, in a case where it is set to -5dB at 3GHz.

[0171] Furthermore, the information processing device 4 can also determine whether a short circuit is occurring based on the transmission loss values ​​at multiple frequencies. For example, in Figure 2C In the case of transmission loss below -5dB at 3GHz and below -7dB at 6.5GHz, the wiring of the object under inspection can be judged to be in a short-circuit state.

[0172] In the event of a wire breakage in connector 120, such as Figure 2D As shown by the dashed line waveform, transmission loss increases throughout the entire frequency range. Particularly, transmission loss diverges towards infinity in the DC region (near 0 GHz). In the high-frequency region, transmission loss becomes relatively small due to capacitive coupling between wirings. However, even so, transmission loss is below -30 dB (above 30 dB). Therefore, if the transmission loss (or the absolute value of the transmission loss) exceeds the specified open-circuit detection threshold at at least any one frequency (in... Figure 2D If the transmission loss in the curve is lower than the open circuit judgment threshold, the information processing device 4 can determine that wiring 111 is in an open circuit state. For example, in Figure 2DWhen the transmission loss is below -20dB (i.e. above 20dB) in the curve diagram, the information processing device 4 determines that the wiring 111 is in an open circuit state.

[0173] Furthermore, in the open-circuit state, transmission loss decreases sharply in the DC region. Therefore, if the transmission loss (or the absolute value of the transmission loss) exceeds the predetermined open-circuit judgment threshold in the DC region, the information processing device 4 can determine that the wiring 111 is in an open-circuit state.

[0174] Alternatively, the information processing device 4 can also perform open / short circuit checks on the wiring 111 based on multiple transmission characteristics (such as reflection characteristics and transmission loss). In this case, for example, if the information processing device 4 determines that the wiring under inspection is normal based on both the reflection characteristic check and the transmission loss check, it will ultimately determine that the wiring under inspection is normal.

[0175] In addition to the open / short circuit checks described above, the information processing device 4 also checks the open circuit status of the wiring 112 based on the DC resistance of the wiring 112 measured by the DC resistance meter 3. Specifically, if the measured DC resistance of the wiring 112 exceeds a predetermined open circuit judgment threshold, the information processing device 4 determines that a break has occurred in the wiring 112 (i.e., the wiring 112 is in an open circuit state). Furthermore, the information processing device 4 displays the judgment result on a display.

[0176] As described above, open / short circuit checks based on transmission characteristics are performed on wirings 111 and 113. Therefore, open / short circuit checks based on the DC resistance meter 3 are not required on wirings 111 and 113. That is, open / short circuit checks on wirings subject to transmission characteristic checks are not required using the DC resistance meter 3. Thus, compared to the comparative example, open / short circuit checks based on the DC resistance meter 3 are reduced. Therefore, inspection efficiency can be improved.

[0177] In the printed wiring board 110, short-circuit checks are performed on wirings 111 and 113 based on transmission characteristics. Therefore, it is not necessary to perform short-circuit checks on wiring 112 adjacent to wirings 111 and 113 (checking whether wiring 112 is in a short-circuit state). Furthermore, in the printed wiring board 110B described later... Figure 5B In this case, the wiring 115, which is not the object of the transmission characteristic check, is not adjacent to the wiring that is the object of the transmission characteristic check. Therefore, a short circuit check is performed on wiring 115.

[0178] As explained above, in the inspection system of the first embodiment, based on the transmission characteristics measured by the vector network analyzer 2, not only are the transmission characteristics of the wiring to be inspected checked, but also the open-circuit and short-circuit states of the wiring are checked. Therefore, the open-circuit / short-circuit checks based on the DC resistance meter 3 can be significantly reduced. Thus, according to this embodiment, the inspection efficiency of the component mounting FPC100 can be improved.

[0179] Furthermore, in this embodiment, all necessary checks can be performed using inspection tools 5 and 6. That is, it is not necessary to prepare separate inspection tools 530 and 540 for open / short circuit checks and inspection tools 650 and 660 for transmission characteristic checks, as in the comparative example. Therefore, according to this embodiment, inspection costs can be reduced.

[0180] Furthermore, in this embodiment, a relatively expensive vector network analyzer 2 and a relatively inexpensive DC resistance meter 3 are combined into a single inspection system. Therefore, compared to the case where all inspections are performed solely by the vector network analyzer—that is, when even inspections of wiring 112, which is not subject to transmission characteristic inspection, are performed by the vector network analyzer—overuse of the vector network analyzer can be suppressed. Thus, the inspection cost can be optimized as a whole for the inspection system.

[0181] <Inspection Process>

[0182] according to Figure 3 The flowchart illustrates a method for manufacturing a printed wiring board, including an inspection process using inspection system 1.

[0183] First, an article sheet S comprising multiple flexible printed wiring boards (FPCs) is manufactured (step S1). This step is the same as step S101 described in the comparative example.

[0184] Next, each printed wiring board 110 of the product sheet S manufactured in step S1 is subjected to an open / short circuit check (step S2). This step is the same as step S102 described in the comparative example.

[0185] Next, an appearance inspection of the product piece S is performed (step S3). This step is the same as step S103 described in the comparative example.

[0186] Next, connectors 120 and 130 are installed on the printed wiring board 110, which was determined to be normal in the open / short circuit check in step S2 and the visual inspection in step S3 (step S4). This step is the same as step S104 described in the comparative example.

[0187] Next, the product sheet S is cut into multiple FPCs (step S5). This step is the same as step S105 described in the comparative example.

[0188] Next, the printed wiring board 110 (component mounting FPC 100) with connectors 120 and 130 installed is subjected to transmission characteristic checks and open / short circuit checks (step S6). Refer to... Figure 4 Here is a detailed explanation of an example of this step.

[0189] First, the transmission characteristics of the high-speed transmission lines (wiring 111, 113) are measured using the vector network analyzer 2 (step S61). Then, the DC resistance of the grounding wiring (wiring 112) is measured using the DC resistance meter 3 (step S62).

[0190] Subsequently, based on the transmission characteristics of the high-speed transmission line measured in step S61, the transmission characteristics of the high-speed transmission line are checked, and an open / short circuit check of the high-speed transmission line is performed (step S63). In this step, the information processing device 4 determines whether the transmission characteristics of wiring 111 and 113 are good based on the transmission characteristics measured by the vector network analyzer 2, and determines whether wiring 111 and 113 are in an open circuit state and whether wiring 111 and 113 are in a short circuit state.

[0191] Additionally, in the open / short circuit check of wiring 111 and 113, either reflection characteristics or transmission loss can be used as transmission characteristics. Alternatively, both reflection characteristics and transmission loss can be used to perform the open / short circuit check of wiring 111 and 113.

[0192] Subsequently, an open-circuit check is performed on the grounding wiring based on the DC resistance measured in step S62 (step S64). In this step, the information processing device 4 determines whether the grounding wiring is in an open-circuit state based on the DC resistance of the grounding wiring, as described above.

[0193] in addition, Figure 4 The inspection process described is just one example. The order of the steps can be changed within the bounds of not contradicting each other. For example, the order of steps S61 and S62 can be changed. Alternatively, steps S61 and S62 can be performed simultaneously. Or step S63 can be performed between steps S61 and S62.

[0194] After step S6, a visual inspection of the component-mounted FPC100 is performed (step S7). This step is the same as step S108 described in the comparative example.

[0195] According to the above-described inspection method for printed wiring boards, it is not necessary to perform open / short circuit checks on wiring 111 and 113, which are the objects of transmission characteristic inspection, using the DC resistance meter 3. Therefore, the inspection efficiency of component mounting FPC100 can be significantly improved.

[0196] <Other examples of flexible printed wiring boards>

[0197] In the description of the above embodiment, the object of inspection is the printed wiring board 110 having wirings 111, 112, and 113. The following description also demonstrates how to effectively inspect printed wiring boards with different wiring structures using this embodiment.

[0198] Figure 5A This is a top view of a component mounting FPC 100A including a printed wiring board 110A and connectors 120A and 130A mounted on the printed wiring board 110A. The printed wiring board 110A has wirings 111 and 114 that are subject to transmission characteristic testing, and wiring 112 that is not subject to transmission characteristic testing. Wiring 112 is disposed between wirings 111 and 114. Compared to the printed wiring board 110, the printed wiring board 110A has wiring 114 (the fourth wiring), which is adjacent to wiring 112 and is subject to transmission characteristic testing, instead of wiring 113.

[0199] When inspecting the component mounting FPC100A (printed wiring board 110A), the transmission characteristics of wirings 111 and 114 are measured using vector network analyzer 2. Furthermore, based on the measured transmission characteristics of wirings 111 and 114, their transmission characteristics are checked, and their open-circuit and short-circuit states are also checked. The inspection method is the same as for wirings 111 and 113. When the component is mounted with FPC100A, it is not necessary to perform open / short-circuit checks on wirings 111 and 114 using DC resistance meter 3. Moreover, since short-circuit checks on wirings 111 and 114 are performed based on transmission characteristics, short-circuit checks on wiring 112 are not required.

[0200] Figure 5B This is a top view of a component mounting FPC 100B including a printed wiring board 110B and connectors 120B and 130B mounted on the printed wiring board 110B. The printed wiring board 110B has wirings 111 and 117 that are subject to transmission characteristic testing, and wirings 112, 115, and 116 that are not subject to transmission characteristic testing. Wirings 112, 115, and 116 are disposed between wirings 111 and 117. Compared to the printed wiring board 110, the printed wiring board 110A has wiring 115 (the fifth wiring), which is adjacent to wiring 112 and is not subject to transmission characteristic testing, and wirings 116 and 117 adjacent to wiring 115, replacing wiring 113.

[0201] When inspecting the component mounting FPC100B (printed wiring board 110B), the transmission characteristics of wirings 111 and 117 are measured using a vector network analyzer 2. Based on the measured transmission characteristics of wirings 111 and 117, their transmission characteristics are checked, and their open-circuit and short-circuit states are also checked. The inspection method is the same as for wirings 111 and 113. When the component mounting FPC100B is used, it is not necessary to perform open-circuit / short-circuit checks on wirings 111 and 117 using a DC resistance meter 3. Furthermore, since short-circuit checks based on transmission characteristics are performed on wirings 111 and 117, short-circuit checks on wirings 112 and 116 adjacent to wirings 111 and 117 are not required. On the other hand, wiring 115 is not adjacent to wirings 111 and 117, which are the targets of transmission characteristic checks. Therefore, wiring 115 is checked for both open circuits and short circuits using a DC resistance meter 3.

[0202] (Second Implementation)

[0203] Next, refer to Figure 6 The inspection system of the second embodiment will be described below. One difference between the first and second embodiments is that multiple components are simultaneously inspected while mounted on the FPC. The second embodiment will be described below focusing on these differences. Furthermore, in... Figure 6 In this embodiment, the same constituent elements as in the first embodiment are assigned to... Figure 1 Same reference numerals as shown in the attached figures.

[0204] like Figure 6 As shown, the inspection system 1A of this embodiment is configured to simultaneously inspect multiple component mounting FPC100C.

[0205] The inspection system 1A includes: a vector network analyzer 2, DC resistance meters 3A and 3B, an information processing device 4, inspection tools 5A and 5B, and multiple inspection tools 6A and 6B. Additionally, the inspection system 1A may also include a retaining mechanism (not shown) for holding the component mounted on the FPC 100C.

[0206] The component mounting FPC100C for the inspection object has a printed wiring board 110C and connectors 120C and 130C mounted on the printed wiring board 110C. The printed wiring board 110C has wiring 111 which is the object of transmission characteristic inspection and wiring 112 which is adjacent to wiring 111 and is not the object of transmission characteristic inspection.

[0207] Connector 120C has connector terminal 121 soldered to the input terminal of wiring 111 and connector terminal 122 soldered to the input terminal of wiring 112. Connector 130C has connector terminal 131 soldered to the output terminal of wiring 111 and connector terminal 132 soldered to the output terminal of wiring 112.

[0208] Inspection tool 5A has an inspection probe 51 electrically connected to the measurement port 21 of the vector network analyzer 2 and an inspection probe 52 electrically connected to the measurement port 31 of the DC resistance meter 3A. Inspection tool 6A has an inspection probe 61 electrically connected to the measurement port 23 of the vector network analyzer 2 and an inspection probe 62 electrically connected to the measurement port 32 of the DC resistance meter 3A.

[0209] Inspection tool 5B has inspection probe 51 electrically connected to measurement port 24 of vector network analyzer 2 and inspection probe 52 electrically connected to measurement port 31 of DC resistance meter 3B. Inspection tool 6B has inspection probe 61 electrically connected to measurement port 22 of vector network analyzer 2 and inspection probe 62 electrically connected to measurement port 32 of DC resistance meter 3B.

[0210] In this embodiment, the vector network analyzer 2 measures the transmission characteristics of the wiring 111 connected between measurement port 21 and measurement port 23, and measures the transmission characteristics of the wiring 111 connected between measurement port 24 and measurement port 22.

[0211] The DC resistance measuring instruments 3A and 3B are the same as those described in the first embodiment. For example, a multimeter is used as the DC resistance measuring instruments 3A and 3B. The DC resistance measuring instrument 3A measures the transmission characteristics of the wiring 112 connected between the measuring port 31 and the measuring port 32. Similarly, the DC resistance measuring instrument 3B measures the transmission characteristics of the wiring 112 connected between the measuring port 31 and the measuring port 32.

[0212] In this embodiment, the information processing device 4 is connected to the vector network analyzer 2, the DC resistance meter 3A, and the DC resistance meter 3B in a manner that enables communication with them. The information processing device 4 simultaneously or sequentially sends trigger signals for starting measurements to the vector network analyzer 2 and the DC resistance meters 3A and 3B. Furthermore, the information processing device 4 receives measurement results from the vector network analyzer 2 and the DC resistance meters 3A and 3B, and based on the received measurement results, determines whether the installation of each component on the FPC 100C is normal. The information processing device 4 then displays the determination result on a display.

[0213] The information processing device 4 checks the transmission characteristics of the wiring 111 based on the transmission characteristics measured by the vector network analyzer 2, and installs an FPC 100C on each component to check the transmission characteristics of the wiring 111, and checks the open-circuit and short-circuit states of the wiring 111. Furthermore, the information processing device 4 checks the open-circuit state of the wiring 112 based on the DC resistance measured by DC resistance meters 3A and 3B, and installs an FPC 100C on each component. The details of these checking methods are the same as in the first embodiment, and therefore their description is omitted.

[0214] In the second embodiment, similar to the first embodiment, open / short circuit checks based on transmission characteristics are performed on wiring 111. Therefore, open / short circuit checks based on DC resistance meters 3A and 3B are not required on wiring 111. Thus, according to the second embodiment, compared to the comparative example, the number of open / short circuit checks based on DC resistance meters 3A and 3B is reduced. Therefore, inspection efficiency can be improved.

[0215] Furthermore, in the second embodiment, multiple component-mounted FPCs can be inspected simultaneously. Additionally, the measurement ports of the vector network analyzer 2 can be utilized effectively and flexibly. Especially when the vector network analyzer has a large number of ports, unused ports can be used for inspecting other component-mounted FPCs. Therefore, the efficiency of using the expensive vector network analyzer can be improved.

[0216] Furthermore, in this embodiment, the object of inspection is an FPC100C consisting of multiple components with the same structure. However, it is not limited to this; the object of inspection may also be an FPC consisting of multiple components with different structures.

[0217] Furthermore, in this embodiment, multiple DC resistance meters 3A and 3B are used. However, it is not limited to this; a single DC resistance meter with multiple measurement ports can also be used to measure the DC resistance of multiple component-mounted FPCs.

[0218] Furthermore, in this embodiment, either or both printed wiring boards 110C may have a third wiring, such as the wiring 113 shown in the first embodiment, which is the object of transmission characteristic inspection. In this case, the vector network analyzer 2 also has a third measurement port electrically connected to one end of the third wiring and a fourth measurement port electrically connected to the other end of the third wiring, and the transmission characteristics of the third wiring can also be measured.

[0219] The above describes two embodiments of the present invention.

[0220] Furthermore, the present invention is not limited to the inspection of flexible printed wiring boards with components such as connectors installed, but can also be applied to the inspection of flexible printed wiring boards before the components are installed.

[0221] Furthermore, this invention is not limited to flexible printed wiring boards, but can also be applied to the inspection of rigid printed wiring boards.

[0222] Furthermore, the present invention can also be applied to the inspection of printed wiring boards with surface mount components other than connectors, such as chip capacitors, chip resistors, or chip inductors.

[0223] Furthermore, this invention can also be applied to the inspection of printed circuit boards that only have wiring for transmission characteristic inspection. In this case, open / short circuit checks of high-speed transmission lines based on DC resistance meters are not required, thus improving inspection efficiency.

[0224] Based on the foregoing description, those skilled in the art may conceive of additional effects and various modifications of the present invention. The present invention is not limited to the embodiments described above. Various additions, modifications, and partial deletions can be made without departing from the concept and spirit of the invention derived from the claims and their equivalents.

Claims

1. An inspection method for inspecting a printed wiring board, the printed wiring board having a first wiring that is an object of transmission characteristic inspection and a second wiring adjacent to the first wiring that is not an object of transmission characteristic inspection, the inspection method being characterized in that... The first wiring and the second wiring are the objects of inspection by the inspection method, and are formed in the insulating substrate of the printed wiring board. The first wiring is a high-speed transmission line. The second type of wiring is power supply lines, grounding wiring, or low-speed transmission lines. The first wiring and the second wiring are configured side by side. The inspection method includes: The vector network analyzer is electrically connected to the first wiring via a first inspection tool and a second inspection tool; The DC resistance meter is electrically connected to the second wiring via the first inspection tool and the second inspection tool; The transmission characteristics of the first cabling were measured using a vector network analyzer; The DC resistance of the second wiring is measured using a DC resistance meter; Based on the transmission characteristics of the first wiring, check the transmission characteristics of the first wiring, and check the open circuit state and short circuit state of the first wiring. as well as Based on the DC resistance of the second wiring, check the open circuit status of the second wiring. Measuring the transmission characteristics of the first cabling includes measuring the transmission loss of the first cabling using the vector network analyzer as the transmission characteristic. Checking the open-circuit and short-circuit states of the first wiring includes: determining that the first wiring is in a short-circuit state when the transmission loss of the first wiring is lower than a specified short-circuit judgment threshold at at least one frequency; And if the transmission loss exceeds the specified open circuit judgment threshold, the first wiring is judged to be in an open circuit state.

2. The inspection method according to claim 1, characterized in that, Measuring the transmission characteristics of the first cabling includes measuring the reflection characteristics of the first cabling using the vector network analyzer as the transmission characteristics. Checking the open-circuit and short-circuit states of the first wiring includes: determining the first wiring to be in a short-circuit state when the characteristic impedance obtained by performing TDR transformation on the reflection characteristics of the first wiring is lower than a specified short-circuit judgment threshold; and determining the first wiring to be in an open-circuit state when the characteristic impedance exceeds the specified open-circuit judgment threshold.

3. The inspection method according to claim 1 or 2, characterized in that, This includes not performing a short-circuit check on the second wiring based on the DC resistance meter.

4. The inspection method according to claim 1 or 2, characterized in that, The printed wiring board also has a third wiring adjacent to the first wiring and serving as the object of transmission characteristic inspection. The inspection method also includes: The transmission characteristics of the third cabling are measured using the vector network analyzer; and Based on the transmission characteristics of the third wiring, check the transmission characteristics of the third wiring, and check the open circuit state and short circuit state of the third wiring.

5. The inspection method according to claim 1 or 2, characterized in that, The printed wiring board also has a fourth wiring adjacent to the second wiring and serving as the object of transmission characteristic inspection. The inspection method also includes: The transmission characteristics of the fourth cabling are measured using the vector network analyzer; and Based on the transmission characteristics of the fourth wiring, check the transmission characteristics of the fourth wiring, and check the open circuit state and short circuit state of the fourth wiring.

6. The inspection method according to claim 1 or 2, characterized in that, The printed wiring board also has a fifth wiring adjacent to the second wiring, which is not the object of transmission characteristic inspection. The inspection method also includes: The DC resistance of the fifth wiring is measured using the DC resistance meter; and Based on the DC resistance of the fifth wiring, check the open circuit status of the fifth wiring.

7. The inspection method according to claim 1 or 2, characterized in that, The printed wiring board is a flexible printed wiring board equipped with a first connector and a second connector. The first connector is electrically connected to the input terminal of the first wiring and the input terminal of the second wiring, and the second connector is electrically connected to the output terminal of the first wiring and the output terminal of the second wiring.

8. The inspection method according to claim 1 or 2, characterized in that, The printed wiring board is a flexible printed wiring board without an installed connector, which is included in the workpiece along with other printed wiring boards.

9. An inspection system for inspecting a printed wiring board, the printed wiring board having a first wiring as the object of transmission characteristic inspection and a second wiring adjacent to the first wiring but not the object of transmission characteristic inspection, the inspection system being characterized in that... The first wiring and the second wiring are the objects of inspection by the inspection method, and are formed in the insulating substrate of the printed wiring board. The first wiring is a high-speed transmission line. The second type of wiring is power supply lines, grounding wiring, or low-speed transmission lines. The first wiring and the second wiring are configured side by side. The inspection system includes: A vector network analyzer has a first measurement port electrically connected to one end of the first wiring and a second measurement port electrically connected to the other end of the first wiring, for measuring the transmission characteristics of the first wiring; A DC resistance measuring instrument has a first measuring port electrically connected to one end of the second wiring and a second measuring port electrically connected to the other end of the second wiring, for measuring the DC resistance of the second wiring; An information processing device is connected to the vector network analyzer and the DC resistance meter to enable communication; The first inspection tool has a first inspection probe electrically connected to the first measurement port of the vector network analyzer and a second inspection probe electrically connected to the first measurement port of the DC resistance meter. as well as The second inspection tool has a first inspection probe electrically connected to the second measurement port of the vector network analyzer and a second inspection probe electrically connected to the second measurement port of the DC resistance meter. The information processing device checks the transmission characteristics of the first cabling based on the transmission characteristics measured by the vector network analyzer, and checks the open-circuit and short-circuit states of the first cabling. The information processing device checks the open-circuit status of the second wiring based on the DC resistance of the second wiring measured by the DC resistance meter. Measuring the transmission characteristics of the first cabling includes measuring the transmission loss of the first cabling using the vector network analyzer as the transmission characteristic. Checking the open-circuit and short-circuit states of the first wiring includes: determining that the first wiring is in a short-circuit state when the transmission loss of the first wiring is lower than a specified short-circuit judgment threshold at at least one frequency; And if the transmission loss exceeds the specified open circuit judgment threshold, the first wiring is judged to be in an open circuit state.

10. The inspection system according to claim 9, characterized in that, The first inspection probe of the first inspection tool is configured to be electrically connected to one end of the first wiring, and the second inspection probe of the first inspection tool is configured to be electrically connected to one end of the second wiring. The first inspection probe of the second inspection tool is configured to be electrically connected to the other end of the first wiring, and the second inspection probe of the second inspection tool is configured to be electrically connected to the other end of the second wiring.

11. The inspection system according to claim 10, characterized in that, The first and second inspection probes of the first inspection tool are configured to be mounted on the connector terminals of the first connector mounted on the printed wiring board. The first and second inspection probes of the second inspection tool are configured to be mounted on the connector terminals of the second connector mounted on the printed wiring board.

12. The inspection system according to any one of claims 9 to 11, which inspects not only the printed wiring board but also printed wiring boards different from the printed wiring board, characterized in that, The different printed wiring boards have a third wiring that serves as the object of transmission characteristic inspection. The vector network analyzer also has a third measurement port electrically connected to one end of the third wiring on the different printed wiring board and a fourth measurement port electrically connected to the other end of the third wiring, for measuring the transmission characteristics of the third wiring.

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