JPH0766022B2 - Wiring board inspection method and apparatus thereof - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wiring board inspection method and apparatus. More specifically, the present invention relates to a wiring board inspecting method and apparatus for checking a wiring pattern for disconnection or short circuit after assembling a circuit board.

[0002]

2. Description of the Related Art Conventionally, a wiring board in which electrode terminals are regularly arranged in the peripheral portion of the board, such as a wiring board on which a drive circuit for a liquid crystal display device is formed or a printed circuit board for other electric circuits, is used. After the electronic parts are assembled, the inspection device for checking the wiring pattern for disconnection or short circuit includes a pin board in which a contact pin is set up for each electrode terminal of the board pattern, and a signal source applied to the contact pin. By applying a minute signal to this pin and measuring the voltage or current, the inspection of the short circuit between wiring due to solder, the presence or absence of parts, the disconnection of the wiring pattern, etc. is performed. In this case, the pin board is prepared for each type of wiring board to be inspected.

A conventional wiring board inspecting apparatus is, for example, as shown in FIG.
As shown in Fig. 21, the wirings 102 and 103 are formed on the surface of the substrate 101.
When inspecting the wiring substrate on which the wiring is formed, a constant voltage power supply 10 having a voltage of V ₀ is applied to one end of the wiring 102 through an ammeter 108.
The pin 104 connected to 7 is brought into contact, the pin 105 connected to the ground via the switch 109 is brought into contact with the other end of the wiring 102, and the pin 106 connected to the ground is brought into contact with the wiring 103. If switch 109 is turned off in this state, the continuity between wirings 102 and 103 will be observed, and the ammeter
If 108 swings, it means that there is a short circuit between the wirings 102 and 103, and if no current flows, it is normal. Further, when a resistance is mounted between the wirings 102 and 103, assuming that the resistance is R ₁ , it is normal if the swing of the ammeter 108 is V ₀ / R ₁ (ampere). On the other hand, if the switch 109 is turned on, the ammeter should swing, but if there is a break in the wiring 102, no current will flow and it can be detected that there is a break.

As another example of the inspection apparatus, as shown in FIG. 22, instead of the constant voltage power source 107 described above, a current I
Connect a constant current power supply 111 of _{0 and} a voltmeter 112 in parallel with the constant current power supply 111, and connect pin 104 to the constant current power supply 111.
And connect between one end of the wiring 102. Similarly to the above, when the switch 109 is turned off and the voltmeter 112 swings to 0V, it indicates that there is a short circuit between the wirings 102 and 103. If the voltmeter does not change, both wirings 102 and 103 are shown.
There is no short circuit between. On the other hand, when a resistor is mounted between the wirings 102 and 103, V = I ₀ × R ₁ which is the product of the constant current value I ₀ and the resistance value R ₁ appears as the swing of the voltmeter 112 and is normal. You can judge whether or not. Further, when the switch 109 is turned on, it is normal if the voltmeter 112 becomes 0 V, and if the swing does not change, it indicates that the wiring 102 is broken, and it is possible to judge the quality.

As another example, as shown in FIG. 23, an AC power source 113 having _a repetition frequency f and a voltage V _a is connected as a power source, and a known power source is connected between the AC power source 113 and the pin 104. A resistor 114 having a resistance value R ₀ is connected in series, a pin 104 is set on one end side of the wiring 102, a pin 106 is set on an electrode terminal 103, and a voltage drop V ₂ across the resistor 114 is measured by an AC voltmeter 115. By this, wiring 102
And the capacitance C of the capacitor 116 mounted between 103 can be measured by C = V ₂ / {2πfR ₀ (V _a −V ₂ )}.

[0006]

Since the conventional inspection apparatus applies current or voltage to each of the wirings 102 and 103 for measurement, an expensive pin board in which contact pins are set up for each electrode terminal of the wiring pattern. Must be prepared for each model of wiring board. Moreover, each electrode terminal of the wiring pattern is 0.
The width is about 3 mm, and there are about three or more in 1 mm width, and the positional relationship between the pin board and the wiring board to be measured also requires high accuracy. In addition, a large number of contact pins must be erected within a limited substrate area, which complicates the structure and requires much labor and time for inspection.

The present invention has been made in order to solve such a problem, and reduces the number of contact pins of a board, and easily inspects whether or not each wiring of a wiring board on which an electronic component is mounted is defective or short-circuited. It is an object of the present invention to provide a possible inspection method and its apparatus.

[0008]

SUMMARY OF THE INVENTION A wiring board inspection method of the present invention is a wiring board inspection for inspecting a wiring pattern of a wiring board in which electrode terminals are regularly arranged and a connection relationship between the wiring patterns. A method for applying an inspection signal, which is a signal for operating the wiring board, to the wiring pattern, and sequentially detecting each signal of the electrode terminals with one scanning needle, and for each of the electrode terminals. The detected signal and the inspection signal are compared , and according to the difference of the comparison,
The output of the counter that counts in synchronization with the inspection signal
The feature is that a defective wiring is specified by using a latch .

In order to identify the defective wiring, the scanning needle is moved.
If the scanning needle is in contact with the electrode terminal by inspection,
Creates an open detection signal that distinguishes when not touched
However, the scanning of the scanning needle does not touch each of the electrode terminals.
Reset the open detection signal at the initial stage,
The detected signal is within the allowable range of the inspection signal
A pulse signal is generated only when
When the open detection signal is set, and when it is set
It is easy to latch the output of the counter of
It is preferable because the defective wiring can be specified.

The wiring board inspection apparatus of the present invention is a wiring pattern
Wiring board inspection device in which the electrode terminals of the battery are regularly arranged.
And (a) an inspection signal including a signal for operating the wiring board.
And (b) a signal from the inspection signal generator is distributed to each of the boards.
And output circuit section to be applied to line patterns, run of one of continuously detecting a signal (c) each electrode terminal
A signal detection unit consisting of a probe , and (d) a detection unit detected from each electrode terminal by the signal detection unit.
Comparator that compares the output signal with each reference voltage
And (e) the output of the comparator and the inspection signal generator.
Signal to identify defective electrode terminal by timing signal
A processing unit, the number of defects of the electrode terminal by the output of the (f) signal processing unit
Consists of a specified control device, the signal processing unit includes a flip-flop circuit issuing an output signal when a normal detection signal is reset for each electrode terminal has been example, pulse the output signal of the flip-flop circuit those composed of a pulse generating circuit for outputting a counter for counting in synchronization with the test signal, a latch circuit for latching the pulse generated the output of the counter in the pulse generating circuit
Is .

Further, the scanning needle according to the present invention is a scanning needle which sequentially scans electrode terminals arranged continuously and detects a signal of each electrode terminal, and a fixed portion to which the scanning needle is fixed, It comprises a rotating shaft provided in the fixed portion, a weight provided at an end of the fixed portion, a stopper for controlling the rotation of the fixed portion, and a control means for controlling the height position of the stopper. the fixing unit has been adapted is fixed to the xy table which can be moved in the plane of the x-axis and y-axis, the tip of the scanning needle by said control means is in contact at a constant pressure to the each electrode terminal is there.

[0012]

According to the present invention, an inspection signal is applied to each wiring pattern of the wiring board, and each electrode terminal is scanned by one scanning needle to measure the signal of each electrode terminal and compare it with the reference voltage. Since the quality of each electrode terminal is determined, the signal of the abnormal electrode terminal is different from the reference voltage, and the quality can be determined between the scanning needle and the electrode terminal. The quality of each electrode terminal can be determined by sequentially scanning the scanning needle on each electrode terminal, and the defective electrode terminal can be found by finally outputting the data. As a result, only one scanning needle needs to be in contact with each electrode terminal, a pin board having contact pins corresponding to each electrode terminal becomes unnecessary, and the invention can be applied to various wiring boards having different arrangements.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The inspection method and apparatus of the present invention will be described below with reference to the drawings. 1 is a schematic diagram showing an embodiment of the system configuration of the inspection apparatus of the present invention, FIG. 2 is a block diagram of the configuration of the test box of FIG. 1, and FIG. 3 is a more detailed block diagram of the test box of FIG. 4 is a cross-sectional explanatory view of the plotter box of FIG. 1, FIG. 5 is an enlarged view of a main part of the scanning needle of FIG. 4, (a) is a side view, (b) is a top view,
(C) is an explanatory view showing the vertical angle of the scanning needle at the time of measurement, FIG. 6 is an operation explanatory view of the fixed part of the scanning needle of FIG. 4, (a) is a side view at the time of non-measurement, (b) is FIG. 7 is a side view during operation, FIG. 7 is an explanatory view showing an angle when the scanning needle of FIG. 4 is scanning, and FIG. 8 is a circuit diagram showing a signal detection buffer amplifier connected to the scanning needle of FIG.

As shown in FIG. 1, one embodiment of the inspection device according to the present invention comprises a control device 1, a test box 2, a dedicated signal source 3, a plotter box 4 and a control box 5. The dedicated signal source 3 and the control box 5 may be put in the test box 2 instead of being kept outside. In the plotter box 4, a wiring board to be measured, such as a wiring board on which a drive circuit for a liquid crystal display device is formed, is installed. In this type of wiring board, electronic components such as ICs are mounted on the front surface side, wiring is formed on the rear surface side, and the electrode terminals of the respective wirings are provided at the peripheral portions so that they can be connected to the respective electrode terminals of the liquid crystal display panel, for example. Are arranged in. The inspection signal emitted from the dedicated signal source 3 passes through the test box 2 and then is input to the plotter box 4. Inside the plotter box 4, each electrode terminal is sequentially brought into contact with a scanning needle to be described later, and a detection signal based on the inspection signal applied to each wiring is picked up via the input terminal of the substrate to be measured. The detection signal is input to the test box 2 again and compared with the reference value to determine whether or not there is an abnormality such as a short circuit or disconnection, and the pass / fail judgment and measurement data are displayed on an output device such as a CRT of the control device 1. To be done. The start and stop of these systems are externally operated by the control box 5.

That is, in the inspection method according to the present invention, an inspection signal is applied to each wiring pattern via the input terminal of the wiring board to be measured, and an output waveform is output for each electrode terminal by one scanning needle. Signals (voltage and timing) are sequentially detected, and the timing signals of the inspection signal and the detection signal are compared with a reference value to determine pass / fail.

Next, the circuit configuration of the test box 2 will be described in detail with reference to FIGS. Test box 2
It is composed of an inspection signal generator 10, an output circuit 20, a comparator 30, a reference voltage generator 9, and a signal processor 40. Reference numeral 60 denotes an electrode terminal signal detection unit in the plotter box, and the substrate 6 to be measured is also inside the plotter box 4. The inspection signal generator 10 can be provided as the dedicated signal source 3 outside the test box 2 as shown in FIG. 1, and in that case, it is not provided inside the test box 2. In FIG. 2, it is considered as one circuit in the test box 2 for convenience.

In the inspection signal generator 10, as shown in FIG. 3, the selector 13 selects the data of the desired signal waveform from the data in the memory 12, and the control circuit 14 produces an appropriate inspection standard display signal. After being converted, the signals are sent from the driver 15 to the output circuit unit 20 and the signal processing unit 40, respectively. For this inspection signal, it is convenient to use a signal that is used when the wiring board is incorporated in an electronic device, such as a drive signal that drives the liquid crystal display device when it is used in a liquid crystal display device. Is.

The output circuit section 20 is a current-voltage conversion circuit (hereinafter,
I / V circuit) 21, a detection circuit 22, and a switch 23. The I / V circuit 21 converts a current into a voltage, and the detection circuit 22 digitizes it so that it can be read by a control device. When an overcurrent flows to the substrate 6 to be measured, if it is determined that the current is an overcurrent based on the detected value, the switch 23 is actuated to shut off the supply of the inspection signal generator 10 to protect the substrate or to prevent the substrate from being measured. It is prevented that an overload is applied to the measurement board 6. If a capacitor or the like is mounted on the board 6 to be measured, an inrush current flows when the power is turned on. Therefore, it is preferable to add a timing circuit to the detection circuit 22.

Further, the comparator section 30 compares and detects the detection signal obtained by the electrode terminal signal detection section 60 and the reference voltage value issued by the reference voltage generator 9 (command from the control device). The open signal and the data detection signal are detected based on the voltage level of the signal and are sent to the next signal processing unit 40. The reference voltage generator 9 may be built in the test box 2, but the reference voltage may be applied by a D / A converter from the control device 1 or the like.

The signal processing section 40 includes a flip-flop circuit (hereinafter referred to as an F / F circuit) 41 and a pulse generation circuit.
42, a counter 43, and a latch circuit 44,
The F / F circuit 41 is reset by a pulse generated at the timing when the scanning needle contacts the electrode terminal by the open detection signal, and is set by the data detection signal. With this F / F circuit 41, the output is set only once for each electrode terminal.

On the other hand, the counter 43 is a counter which operates in synchronization with the inspection standard display signal so that it is activated by the inspection standard display signal, counts up with the clock of the inspection standard display signal, and is reset by the synchronizing signal. is there. Since it is synchronized with the standard display signal for inspection, it is also synchronized with the substrate under measurement and is used for determining the signal timing unique to the electrode terminal of the substrate under measurement.

The counter 43 is latched by the latch circuit 44 at the timing of setting the output of the F / F circuit 41. Therefore, the output of the counter 43 is latched only once by scanning one place of the electrode terminal.

Test box 2 constructed as above
Is connected to an external control device 1 by an interface section 51, and the interface section 51 is composed of an interface driver, and outputs the control signal of the inspection signal generating section 10 and the output circuit section 20 and a signal processing section. Instructions such as output of the determination signal from 40 and input of the reference voltage signal are issued from the control device 1. Note that the DC power supply unit 52 is a unit that converts, for example, an AC 100 V power supply into a DC power supply in order to operate this apparatus.

The control box 5 instructs the control device 1 to start the inspection and display the result.
As described above, a dedicated case may be provided, but it may be attached to the test box 2 instead. In the present invention, the installation location is not particularly limited.

Next, the plotter box 4 will be described.

The plotter box 4 serves as a potential detector 60 for the electrode terminals, and as shown in FIG.
The fixed part 70 of the scanning needle 71 and the xy table 61 mounted on the
A microcomputer 62 for controlling movement in the y direction, a step motor 63
It consists of The scanning needle 71 can also be moved in the z-axis direction,
The movement in the z-axis direction is performed by a cylinder (not shown) and control means such as a compressed air source or an electromagnetic drive source, and is controlled by the microcomputer 62. The microcomputer 62 is controlled by the control device 1. Further, a jig 64 for fixing a substrate to be measured for mounting the substrate to be measured is attached to the plotter box 4, and the substrate 6 to be measured is mounted on the jig 64.

The control device 1 is provided with an interface section for controlling connection with the test box 2 and a D / A converter section, and a plotter box control section for controlling connection with the plotter box 4. In addition, the control device 1
If necessary, a printer and a hard disk for storing a scanning program, accumulating measurement data, and the like can be attached.

As shown in FIG. 5, the scanning needle 71 is made of a metal such as hard steel wire and has a diameter of 0.5 to 3.0 mm and a length of 30 to 60.
A fixed part 70 having a cylindrical needle holder 72, which is a needle of about mm.
It is fixed to. A signal detection screw 73 is attached across the body of the needle holder 72, and the detection screw 73 functions as a connection terminal for transmitting the detection signal input to the scanning needle 71 to the comparator unit 30. . Also, the scanning needle 71
It also has a fixed function. Further, a needle fixing position adjusting screw 74 for adjusting the protruding length of the tip of the scanning needle 71 is provided at the bottom of the needle holder 72. Further, a weight 75 is provided on the opposite side of the fixed portion 70 from the tip of the scanning needle 71. Further, a rotary shaft 76 is provided at an appropriate position of the fixed portion 70 so that the scanning needle 71 rotates in the vertical direction so that the tip of the scanning needle 71 comes into contact with the substrate 6 to be measured. The rotary shaft 76 is supported by, for example, the side wall of the xy table 61. The contact angle (that is, the angle between the substrate to be measured 6 and the scanning needle 71, θ) and the contact pressure are determined by the tightening degree of the needle fixing position adjusting screw 74, and the protruding length of the scanning needle and the weight and position of the weight 75. Since it can be easily adjusted by, any measurement posture can be obtained. Normally the contact angle θ is 30
The contact pressure is 5 ° to 80 ° and the contact pressure is 5 to 40 gr.

The contact method of the scanning needle will be described in more detail. The position of the fixed portion 70 in the z-axis direction is controlled by a pen cylinder 77 as shown in FIG. 6, for example. That is, the pen cylinder 77 communicates with a compressed air source (not shown) that generates high-pressure air via the pipe 78. As shown in FIG. 6A, the fixed portion 70 has a stopper 79 at the tip of the pen cylinder 77 engaged with a pin 80 provided at one end of the fixed portion 70, so that the fixed portion 70 is substantially horizontal as shown in FIG. 6A. The scanning needle 71 does not contact the substrate 6 to be measured because the scanning needle 71 is kept in the position. At the time of measurement, as shown in FIG. 6B, a valve (not shown) provided in the middle of the pipe 78 is actuated by the control of the control device 1 so that the compressed air source is supplied into the pen cylinder 77. High-pressure air is sent in, and pushes the stopper 79 upward to release the engagement with the pin 80. This allows
The weight of the weight 75 causes the fixed portion 70 to rotate about the rotary shaft 76, and the tip of the scanning needle 71 comes into contact with the substrate 6 to be measured, so that the posture becomes measurable. The means for pushing up the stopper 79 is not limited to the compressed air source, but may be another control means such as an electromagnetic drive source.

The electrode terminals of the wiring board are often provided at right angles on the peripheral edge of the wiring board, as shown in FIG. 7, for example, and all electrode terminal groups 81 and y in the x-axis direction are provided.
Since it is necessary to scan both the electrode terminal groups 82 in the axial direction, as shown in FIG. 7, it is preferable that the angle α between the scanning needle and the x-axis direction as seen in a plan view is about 45 ± 30 °. .
As a result, scanning can be performed in the forward direction along the x-axis and the y-axis.

The scanning needle 71 and the fixed portion 70 are placed on the xy table 61 together with the signal detection buffer amplifier, and the control device 1 and the microcomputer 62 carry out xyz axis control.

As shown in FIG. 8, the scanning needle 71 has resistors R ₁ and R ₂ connected between the test box 2 and a reference voltage defined by the controller 1, and the tip of the resistor is connected to an electrode terminal. , And the detected signal is sent to the test box 2 via the buffer amplifier 83. This resistance R ₁ , R
By inserting ₂ , the detection signal becomes the reference voltage value when the scanning needle 71 is not in contact with the electrode terminal, and the output value of the electrode terminal is sent when the scanning needle 71 is in contact with the electrode terminal. In addition, since it is possible that the operating voltage range of the test box 2 is narrower than the output voltage range of the measured board 6, the measured board can be obtained by obtaining an output signal from a contact having an appropriate resistance division ratio R ₁ : R _2. The voltage range of 6 is R ₂ / (R ₁
It can be set to be + R ₂ ), which is convenient.

Next, the inspection method of the present invention will be described in detail by taking a wiring board on which a drive circuit for a liquid crystal display element is formed as an example.

First, the inspection signal generator 10 causes the memory 12 and the control circuit 14 to generate a signal suitable for the substrate to be measured. For example, LCD drive (640 x 400 dots)
In the case of a wiring board for use, the common terminal generates a selection signal and the segment terminal generates a display signal.

A standard display signal for inspecting the segment terminals is written in the memory 12. The signal to be written is n shown in FIG.
This is a signal having a number of time division phase differences. In this case n
= 16. This signal corresponds to the position number of the segment. When the sync signal is generated, segment 1 displays 16 counts of clock pulses, 32 counts, and so on every 16 counts, segment 2 is delayed by 1 count clock pulse from segment 1, and segment 3 is counted 1 more clock pulse than segment 2. Delay ... and segment 16
It shifts by 1 each. Segment 17 has the same contents as segment 1, and repeats until the last segment. As a result, the segment electrode terminals are classified into 16 phase difference sets.

Next, in the output circuit section 20, the circuit current of the substrate 6 to be measured is measured, and when the current out of the specified range flows, the switch 23 is automatically turned off. That is, when the circuit board 6 to be measured has an abnormality, the circuit current changes. Therefore, the voltage conversion value of the circuit current value is digitized by the A / D converter or the comparator of the detection circuit 22 and sent to the control device 1. In case of overcurrent, the switch 23 is turned off. switch
23 is controlled by the control device 1 and the detection circuit 22, but as described above, since a capacitance such as a bypass capacitor is generally mounted on the measured substrate 6, an overcurrent flows when the power is turned on. A measurement timing circuit is provided to measure the current value after a fixed time.

After confirming whether the analog value that directly influences the measurement among the signal values set by the inspection signal generator 10 is also the set value, if it is within the set value, the plotter box 4 It is sent to the substrate 6 to be measured installed inside.

In the comparator section 30, the detection signal has a specified voltage value when the scanning needle 71 is not in contact with the electrode terminal, and the output value when the scanning needle 71 contacts the substrate 6 to be measured does not normally have the specified voltage value. The detection signal is compared with the reference voltage which is the output voltage (threshold value of the expected output value) of the D / A section set by the control device 1 to detect the open signal of the scanning needle 71 and the display signal. .

For example, as shown in FIG. 10 and FIG. 11 when the output waveform at the time of operation is shown, in the case of the output waveform at the time of the bias of 1/15 of the operating voltage, V ₁ is the V _DD voltage of the substrate and V ₁₆ is the voltage of the substrate. V
_{Since the EE} voltage is V ₁ = 5V and V ₁₆ = −20V at the time of inspection, each potential difference from V _{1 to} V _16, that is, V ₁ −V ₂ , V
₂ -V ₃ ... V ₁₅ -V ₁₆ becomes (V ₁ -V ₁₆₎ /15=1.67V. Therefore, the individual voltages are V ₁ = 5V, V ₂ = 3.33
V, ... V ₁₅ = -18.33 V, V ₁₆ = -20 V. The output waveform is resistance-divided on the basis of the reference voltage V _ref of FIG. 8 according to the ratio of R ₁ and R ₂ so that it will fall between the upper and lower display detection ranges of the comparator section during discrimination. In this embodiment, R ₁ : R ₂ = 2: 1 and the reference voltage V _ref is 0.
Since it is V, it is resistance-divided into 1/3 with 0V as a reference. Therefore, V ₁ = 1.67V, V ₂ = 1.11V, ... V ₁₅
= −6.11V, V ₁₆ = −6.67V.

Further, as shown in FIG. 10 (b), V ₀₁
By setting (0.05 V) and V ₀₂ (−0.05 V) as the upper threshold value and the lower threshold value of the comparator, respectively, the reference voltage V _ref of FIG. Is detected and a detection signal V _ON of 5 V is opened. Similarly, as shown in FIG. 11, in the + side operation, the peak voltage V ₁ of the discrimination signal is, for example, a detection range of 1.80 to 1.50 V between the upper threshold V ₁₁ of the comparator and the lower threshold V ₁₂ of the comparator. In this case, the comparator section obtains a detection signal with an output of 5 V, and in the negative side operation, as shown in FIG. 11B, the peak value voltage V ₁₆ of the discrimination signal is equal to the threshold value V _{17 of the} upper and lower comparators. V ₁₈
When the detection range is −6.31 to −6.70 V, the detection signal of output 5 V is obtained in the comparator section.

Next, the output waveform at the time of short circuit will be described.

For example, in the case of common output of a substrate for a liquid crystal drive (640 × 400 dots), from terminals 1 to 200 (200 terminals are provided on each side of the substrate) for signals of 200 cycles. Since the display signals are generated one cycle at a time, if the terminals are short-circuited, the display signal value of the shorted terminals will be the average value of the shorted terminals and will not reach the detection voltage level. If the terminals are open, the signal itself will not be input. No detection signal is generated.

As shown in FIGS. 12A to 12C,
In the case of normal common outputs 1 to 3, specified V ₁₆ = −6.67
A voltage of V can be obtained. For example, as shown in Fig. 12 (d),
When the common terminal 1 and the common terminal 2 are short-circuited, the short-circuit output value is an average value, so V _S1 = (V ₂ +
V ₁₆ ) /2=−2.78V, and the specified detection level V ₁₆ =
No display signal is detected because it does not reach -6.67V. Further, as shown in FIG. 12E, when three of the common terminals 1 to 3 are short-circuited, V _S2 = (V ₂ + V ₂ +
V ₁₈₎ /3=-1.48V next display signal is not detected.
Further, the above operation can be similarly performed for the measurement of the segment pad. That is, in the case of the segment terminals, the n kinds of signals set by the signal source are generated by shifting by one cycle for each terminal, so that in the case of short-circuiting, the display signal becomes an average value and does not reach the detection level. Similarly, when the terminal is open, the detection level is not reached.

Further, not only when the circuit is short-circuited or open, but also when the function is defective such that the connected electronic component does not operate, the signal generation position shifts, so that the signal generation position can be detected. For example, if the IC connected to the wiring connected to the electrode terminal is defective, the specified output signal is not generated and the display signal is not detected. Therefore, it is detected that the function is defective even if they are mechanically connected.

FIG. 13 shows a concrete circuit example of the comparator section 30. The detection signal from the plotter box 4 is input terminal 31
Buffer amplifier (for example, LF356 manufactured by National Semiconductor (hereinafter referred to as NS))
N) and the comparators 33a and 33b, the open signal A is sent to the signal processing unit 40, and further the comparators 34a to 35
b (for example, LM319N manufactured by NS company), and OR gate 36a (for example, 74HC32A manufactured by Toshiba Corporation)
P), NAND gate 37 (for example, 74 manufactured by Toshiba Corp.)
HC00AP) and the OR gate 36b, and sent as a detection signal B to the signal processing unit 40. One terminal of the NAND gate 37 is a one-shot pulse generation IC which is a timing circuit for preventing malfunction due to time delay.
38 (for example, 74HC123AP manufactured by Toshiba Co., Ltd.), and the AND gate 39 (for example, manufactured by Toshiba Co., Ltd.) receives the reset signal from the controller 1 and the synchronizing signal for inspection at one input terminal of the OR gate 36b. 74HC08AP) output signal is input. In Figure 13, R ₄ is 620 Ω and R ₅ is 10
⁵ Ω, R ₆ is 10 ³ Ω, R ₇ is 50 kΩ, R ₈ is 1.5 kΩ,
C ₂ is 100 pF and the power source is 5V.

On the other hand, the signal processing section 40 has a counter 43 shown in FIG.
Section and the latch circuit 44. As shown in the schematic circuit diagram of the counter section, a counter synchronized with the test signal generating section 10 and the board under test 6 by using the clock and the synchronizing signal in the signal from the test signal generating section 10. Operate 43. The counter 43 counts up with the clock reset to the initial value by the synchronization signal. In FIG. 14, 431 is an inspection signal generator.
Input terminal of clock signal from 10, 432 is input terminal of synchronization signal, 433 is IC for NOR gate (for example,
Toshiba Corporation 74HC02AP, 434 and 435 are ICs for counting (for example, Toshiba Corporation 74HC
161AP), 436 are LEDs, 441, 442 are input sections for inputting latch pulses, 443, 444 are latch ICs (for example, Toshiba Corporation 74HC375AP), R ₁ is a resistance of 510 Ω, and R ₂ is 0.5. kΩ, R ₃ is 1.5 kΩ, C ₁ is
It is a 100 pF capacitor.

Further, as shown in FIGS. 15A and 15B as specific examples of the F / F circuit 41 and the pulse generating circuit 42 of the signal processing unit 40, the open signal A detected by the comparator unit 30 and the detection of the open signal A are detected. When the signal B is input to the reset terminal and the data terminal of the F / F circuit 41, the scanning needle 71 is brought into contact with the electrode terminal to cause the F
The output of the / F circuit 41 is reset and set by the next detection signal, and the F / F circuit is set once for each contact of the electrode terminal.
Generates 41 set signal.

Thus, even if a plurality of detection signals are input by one contact of the electrode terminal of the scanning needle 71, the circuits after the F / F circuit 41 do not operate and become stable.

Further, it is preferable that the scanning needle 71 is provided with a malfunction preventing circuit due to the influence of jittering immediately after contact with the electrode terminal. A pulse is generated at the output set timing of the F / F circuit 41, the output of the counter 43 is latched at the generated timing, and the latched output is used by the control device 1.
Send to.

In FIG. 15, 421 is a buffer amplifier and 42
2 is an inverter, 423 is an OR gate, 424 and 425 are a combination of monostable multivibrator, and 426 is a chattering prevention circuit. Also, 411 is F /
An IC that constitutes an F circuit, for example, 74H manufactured by Toshiba Corporation
C74AP and 428 are AND gates. Arrow P in FIG.
Generate a pulse at the falling edge of the pulse as shown in
At the arrow Q, a pulse is generated at the rising portion of the pulse.

Next, specific signal processing in the signal processing section will be described with reference to a time chart.

For example, when measuring the common pad,
As shown in FIG. 16, the scanning waveform (a) is not near 0 when the scanning needle 71 is in contact with the eighth and ninth common electrode terminals 608 and 609, for example, and is near 0 when opened. Therefore, first, the open detection signal (b) is obtained by the comparator section. The open detection signal (b)
At the trailing edge of the pulse, a stabilization delay (c) is provided to prevent a malfunction due to waveform breakage caused by jittering of the scanning needle, etc. Then, the F / F reset signal (d) is activated when the stabilization delay (c) falls. Next, the peaks reaching the display detection range on the upper and lower sides of the scanning waveform (a) are read, and the detection signal (e) is obtained when the peak signal is generated. Detection signal (e)
Then, the F / F output (f) is set. Once the F / F output (f) is set, the set state continues as it is until the F / F reset signal (d) is activated, and then even if a new pulse of the detection signal (e) is detected, it does not change. Further, a pulse output (g) is obtained at the rising portion of the F / F output (f). The pulse output (g)
The output (h) of the counter 43 which counts (1 to 200 in this embodiment) in synchronization with the inspection signal is latched by
Latch with 44. For example, the output of the 8th electrode terminal causes the display signal to be generated at the 8th of the counter (1 to 200), a latch pulse is made at that timing, and the output of the counter (8 of 1 to 200) is latched by the latch pulse. Latch with (i). This latched 8 (8-bit binary, from the lower order, Lo, Lo, Lo, Hi, Lo, Lo, L
The outputs of (o, Lo) are input into the control device 1 and are arranged as a read value (k) for each pulse at the read timing (j) to be measured data. This operation is from electrode terminal 1
It is done up to 200 sequentially. FIG. 17 shows a flowchart of a measurement example at this time.

Further, as shown in FIG. 18, the segment electrode terminals are similarly measured. Here, as an example, the sixth to ninth segment electrode terminals 806 to 809
Of these, there is a short part 800 between the 7th and 8th. In this case, the peak of the scanning waveform (a) obtained when the seventh and eighth segment electrode terminals 807 and 808 are contacted is reduced in size by averaging the peaks of the two pads (FIG. 12 (d)). Therefore, the display detection range of (a) is not reached, and the pulse of the detection signal (e) is not generated in that section. Therefore, the segment electrode terminal 80
The F / F output signal (f) obtained when 7 comes into contact with the scanning needle 71 remains reset after the output of the 6th segment is reset, and the 9th segment pad 809
The reset state is maintained until the pulse of the detection signal (e) is obtained from. Therefore, since the 7th and 8th pulse output (g) pulses and the latch output (i) are not present, the reading value (k) finally obtained skips to 9 after 6th. As a result, it is determined that the seventh and eighth electrode terminals are abnormal. FIG. 19 shows a flowchart of a measurement example at this time. It should be noted that the segment terminals are also measured by the number corresponding to the terminal number of the electrode terminal, but since the number of terminals is large, it is handled by the number that modulo n (n = 16 in this embodiment). .

FIG. 16 and FIG. 18 obtained as above
On the basis of the read value (k) shown in (1), the control device 1 makes a pass / fail determination, and a terminal number not included in the read value (k) is determined to be defective. As a result of this determination, for example, the defective terminal number is displayed on the display according to the procedure of the flowchart shown in FIG. In this display, only the defective electrode terminals can be displayed together with the numbers, or all the numbers can be displayed as good or bad.

Further, in order to prevent malfunction due to measurement waveform division due to poor contact or malfunction due to time delay of the signal processing section, one shot pulse generation I is shown in FIG.
A latch pulse acceptance timing circuit is preferably provided, as shown at C38.

In the above-mentioned embodiment, the inspection of the liquid crystal drive printed circuit board has been described as an example. However, the fixing jig of the plotter box and the inspection signal generating section in the test box should have specifications corresponding to the board to be measured. Can be similarly applied to other wiring boards. That is, if the substrate is one in which electrode terminals for connection to an external circuit such as a plasma display or a thermal head array are regularly arranged, the inspection can be easily performed as in the above embodiment.

[0057]

According to the present invention, a wiring board having a large number of output terminals can be inspected with a single scanning needle, and even if the wiring board changes, the same device can be used by changing the inspection signal. Inspection can be performed, and jig manufacturing cost can be reduced. Moreover, the control device can display the result of pass / fail, and stable measurement can be easily performed in a short time.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing an example of a system configuration of an inspection apparatus of the present invention.

FIG. 2 is a block diagram of the test box of FIG.

FIG. 3 is a more detailed block diagram of the test box of FIG.

4 is a cross-sectional explanatory view of the plotter box of FIG.

5A and 5B are enlarged views of a main part of the scanning needle in FIG. 4, in which FIG. 5A is a side view, FIG. 5B is a top view, and FIG. 5C is an explanatory view showing vertical angles of the scanning needle during measurement.

6 is an operation explanatory view of a fixed portion of the scanning needle of FIG. 4,
(A) is a side view at the time of non-measurement, (b) is a side view at the time of operation.

FIG. 7 is an explanatory diagram showing angles in a plan view at the time of scanning by the scanning needle of FIG.

FIG. 8 is a circuit diagram showing a signal detection buffer amplifier connected to the scanning needle of FIG.

9 is a graph showing a timing of a signal source pattern of the inspection device of FIG.

10 is a diagram showing an example of a scanning waveform of the inspection apparatus of FIG. 1, (a) shows a peak value of the waveform, and (b) shows a detection range at the time of open detection.

11A and 11B are diagrams showing an example of scanning waveforms of the inspection apparatus in FIG. 1, where FIG. 11A shows a + side operation and FIG. 11B shows a − side operation.

12 is a diagram showing an example of a scanning waveform when the inspection device of FIG. 1 is short-circuited.

FIG. 13 is an example of a circuit diagram of a comparator section showing an embodiment of the inspection apparatus of the present invention.

FIG. 14 is an example of a circuit diagram of a counter section showing an embodiment of the inspection apparatus of the present invention.

15 is an example of a circuit diagram of a signal processing unit showing an embodiment of the inspection apparatus of FIG.

16 is a diagram illustrating an output signal when a common electrode terminal is inspected by using the inspection device of FIG.

17 is a flowchart for inspecting the common electrode terminal shown in FIG.

FIG. 18 is a diagram illustrating an output signal when a segment electrode terminal is inspected by using the inspection device of FIG. 1.

FIG. 19 is a flowchart for inspecting the segment electrode terminal shown in FIG.

FIG. 20 is a flowchart for displaying a test result of the inspection device of FIG.

FIG. 21 is an operation explanatory view showing an example of a conventional inspection device.

FIG. 22 is an operation explanatory view showing another example of the conventional inspection apparatus.

FIG. 23 is an operation explanatory view showing still another example of the conventional inspection apparatus.

[Explanation of symbols]

 1 Controller 2 Test box 3 Dedicated signal source 4 Plotter box 5 Control box 10 Inspection signal generator 20 Output circuit 30 Comparator 40 Signal processor 60 Electrode terminal signal detector 71 Scanning needle

Claims (4)

[Claims] 1. A wiring board inspecting method for inspecting a wiring pattern of a wiring board in which electrode terminals are regularly arranged and a connection relationship between the wiring patterns, wherein the wiring board is operated on the wiring pattern. A test signal composed of a signal to be applied is applied, and each signal of the electrode terminals is set to 1
Sequentially detected by the two scanning needles, the signal detected for each electrode terminal is compared with the inspection signal , and the difference in the comparison is detected.
Of the counter that counts in synchronization with the inspection signal
A method for inspecting a wiring board, wherein a defective wiring is specified by using an output as a latch . 2. The defective needle is identified by contacting the electrode terminal with the scanning needle by the scanning of the scanning needle.
An open that distinguishes between when and when not in contact
A detection signal is formed, and the scanning of the scanning needle causes the scanning of the electrode terminal.
The open detection signal at the initial stage when they start contacting each other
Reset, the detected signal is the inspection signal
Generate a pulse signal only when it is within the allowable range, and
The open detection signal is set by the loose signal, and the
Latching the output of the counter when turned on
The inspection method according to claim 1, which is performed by. 3. The electrode terminals of the wiring pattern are regularly arranged.
A wiring board inspection device, comprising : (a) an inspection signal including a signal for operating the wiring board.
And (b) a signal from the inspection signal generator is distributed to each of the boards.
And output circuit section to be applied to line patterns, run of one of continuously detecting a signal (c) each electrode terminal
A signal detection unit consisting of a probe , and (d) a detection unit detected from each electrode terminal by the signal detection unit.
Comparator that compares the output signal with each reference voltage
And (e) the output of the comparator and the inspection signal generator.
Signal to identify defective electrode terminal by timing signal
A processing unit, the number of defects of the electrode terminal by the output of the (f) signal processing unit
And a flip-flop circuit that outputs an output signal when a normal detection signal is obtained by resetting each electrode terminal, and a pulse by the output signal of the flip-flop circuit. a pulse generating circuit for outputting a composed of a counter for counting in synchronization with the test signal, a latch circuit for latching the pulse generated the output of the counter in the pulse generating circuit wiring
Board inspection device. 4. A scanning needle for sequentially scanning continuously arranged electrode terminals to detect a signal from each electrode terminal, the fixed portion having the scanning needle fixed thereto, and the fixed portion provided on the fixed portion. The rotating shaft, a weight provided at the end of the fixed portion, a stopper that controls the rotation of the fixed portion, and a control unit that controls the position of the height of the stopper, the fixed portion being an x-axis. And a scanning needle fixed to an xy table movable in the plane of the y-axis, and the control means causes the tip of the scanning needle to contact the electrode terminals with a constant pressure.