JPH0197878A - Testing method of divided wirings - Google Patents

Abstract

PURPOSE:To test a printed wiring board effectively in a short time, when conduction/insulation tests are performed with a divided type head, by not testing all pins, but executing the tests especially using programs. CONSTITUTION:Grid shaped contact pins 4, which are provided in a divided type head 3, are compressed to a circuit pattern 2 of a printed wiring board 1. Testing voltages are applied by changing switching circuits. The connections of the circuit pattern are checked in this wiring test. In this constitution, a conduction testing device 6 and a insulation testing device 7 are provided as constituent devices, which are formed in a testing and judging part 5 in the divided type head in the form of test programs. When the addresses of the pins under tests are determined, FROM addresses are viewed. Whether the address is in the inside or outside of a region is judged. When the address is at the outside of the region, the conduction test is not conducted. When it is in the inside, the conduction test is conducted with the device 6 only at the time of the initial head access. The point of the pin having the highest number among the divided net is obtained for every head location, and the insulation test is conducted with the device 7. The test is not conducted when the head is located at the point having lower number.

Description

Detailed Description of the Invention [Summary] The present invention relates to a test method for inspecting the insulation resistance of a circuit pattern on a printed wiring board, and in particular, the present invention relates to a test method for testing the insulation resistance of a circuit pattern on a printed wiring board. The purpose is to provide a method for effectively testing the printed wiring board pattern by pressing the grid-shaped contact pins provided on the dividing head and applying the test voltage while being switched by a switching circuit. In the wiring test method for testing the resistance of the contact pin, the test/judgment section judges the previous from address in order to apply a test voltage to the contact pin, and does not perform a continuity test when it is outside the head area. If so, there is a way to test only at the first head access, and to find the oldest numbered point among the parts of the net divided for each head location, perform the insulation test at that point, and avoid testing on the smaller numbered heads. The configuration includes means for

[Industrial Field of Application] The present invention relates to a test method for testing the insulation resistance of a circuit pattern on a printed wiring board.

Conventionally, there is a method in which contact pins are pressed against all grid points in the required test area of a printed wiring board, and at this time, a dividing head that covers the divided area is used and the head is moved to the entire area to perform the test. However, since the inspection points overlapped, the test took a lot of time.

Therefore, there was a need to develop a method that could perform simple and accurate tests in a short period of time.

[Prior art] Printed wiring boards are becoming denser and more multi-layered, and when testing their wiring patterns, there are two methods: an all-pin method that has contact pins (probes) at all grid points in the test area, and an all-pin method that has contact pins (probes) at all lattice points in the test area. There is a method of dividing the head into two parts and using a dividing head.

In the all-pin method, for example, consider a 2.5 mm grid position and attach contact pins (probes) that make contact with the switching at all of the positions, and when the pins are pressed against the board, the test voltage is switched for each pin by a switching circuit. , apply.

At this time, it is possible to inspect the electrical condition of the wiring pattern in a short time, which is close to that in actual use.

Further, in the divided head method, a test head of a size obtained by dividing the test area is used to test the entire area by mechanical scanning (movement). In this method, the number of test terminals is not enormous, the price is not extremely high, and the leakage current inside the test device is small, so the insulation test accuracy can be improved.

[Problems to be Solved by the Invention] The all-pin method had the disadvantage that the number of test terminals was enormous, and it was therefore expensive. Furthermore, since the number of test contact pins is large and the switching circuits are inserted in series, there is a drawback that leakage current increases and the accuracy of the insulation test decreases. The split head method requires time to move the head and increases the number of insulation tests, which is natural from the operational principle, but it also has the major disadvantage of testing the same test points over and over again. That is, not only does the test time become longer, but also a plurality of failure result messages are output for failure points occurring near the divided areas, making it difficult to distinguish between them.

SUMMARY OF THE INVENTION An object of the present invention is to improve the above-mentioned drawbacks and to provide a method for effectively testing patterns on printed wiring boards in a short time without repeating tests in the split head method.

[Means for Solving the Problems] FIG. 1 is a diagram showing the basic configuration of the present invention. In FIG. 1, 1 is a printed wiring board, 2 is a circuit pattern, 3 is a dividing head, 4 is a contact pin, 5 is a test/judgment section, 6 is a continuity test means, and 7 is an insulation test means.

In the wiring test method, the connection of the circuit pattern is inspected by pressing the grid-shaped contact pins 4 provided on the dividing head 3 onto the circuit pattern 2 of the printed wiring board 1 and applying a test voltage while being switched by a switching circuit. The present invention has the following configuration.

That is, in order to apply a test voltage to the contact pin 4, the test/judgment unit 5 judges the previous from address, and if it is within the head area, a continuity test is not performed, but if it is within the head area, it is determined at the time of the first head access. and means 7 for determining the oldest numbered point among the parts of the net divided for each head location and performing the insulation test at that point, and not performing the insulation test on the smaller numbered heads. It is important to be equipped.

[Function] The present invention has addresses assigned to areas in order for the dividing head to access the circuit pattern on the board, and is applicable to cases where two dividing heads are used or one head is moved after testing. be done.

For example, the continuity test means 6 is prepared as a configuration means in the test/judgment section 5 in the dividing head in the form of a test program.
and insulation testing means 7. Then, when the dividing head is brought in and the address for the pin to be tested is determined, the from address (terminal address on the voltage application side)
to determine whether the address is within or outside the head area. When it is outside the area, the continuity test means 6 does not perform a continuity test, but searches for another pin and enters the test.When it is inside the area, the continuity test means 6 performs a continuity test only at the first head access.

Also, among the nets divided by head location,
The point of the oldest numbered pin is determined, and an insulation test is performed at that point using the insulation test means 7. Also, do not perform an insulation test on the smaller numbered heads.

[Embodiment] FIG. 2 shows an operation flowchart in the case where a test program is installed and a test is performed as an embodiment of the present invention.

Start the exam, bring in one program, and judge.

In step (2), it is determined whether the address of the contact pin is within the head area.

Here, the term "inside the head area" refers to an area accessed by two heads. If the determination is negative, no test is performed and the data is ignored. If the determination is affirmative, it is determined in step (2) whether or not it is at the beginning of the net. Net is a word that refers to a group of wiring terminals on a test program. If the judgment is positive, perform "from set only". Here, "from set" refers to applying one side of the power supply voltage to the contact pin to bring it into contact with the circuit pattern on the board. At this time, only the from set was performed, and the next test program was imported without testing. When the judgment in step ■ is negative, it is checked in step ■ whether the end of the net is reached. If it is not finished, move on to step ■. If the answer is NO in step (2), it is determined whether the previous from address set is within the head area. If the result is negative because it is out of the area, even if the continuity test is performed, an error will only occur. Therefore, in step (2), it is determined whether or not the C mode (continuity test mode) is selected. If not, just set from from by giving a continuity test command. Also, if it is affirmative, you can ignore it.

If step (2) is affirmative, it is within the range, so proceed to step (2). In step (2), it is determined whether the immediately previous from address is within the same head. If it is affirmative (inside), there is a possibility that the same pin will be tested twice, so in step (2) it is determined whether or not that head is accessing for the first time. If no, the second test will not be conducted, so proceed to step ■. If step (2) is negative or step (2) is affirmative, the process advances to step (2) to execute the continuity test command. If step (2) is affirmative, step (2) determines the smallest address within the head area of the net.

This is because the first address at the end of the net is not necessarily the smallest numbered address, and the smallest numbered address of the oldest numbered head has a larger value than the oldest numbered address of the smallest numbered head. Then, in step O for that address, it is determined whether it is on the side of the head with the highest number. If no (lower number), it is determined in step (2) whether or not it is the first head location. When it is affirmative and when it is negative (older number) at step 0, proceed to step @ to perform an insulation test. If step (2) is negative, the next process is not performed.

Next, as an embodiment of the present invention, FIG. 3 shows an example of a printed wiring board, and FIG. 4 shows an example of a program therefor. Third
The board in the figure is divided into 10 head areas from (1) to αφ shown in parentheses, and the check point is 1.
to 17 are shown.

In FIG. 4, the head location column shows the numbers of areas in which two heads are used, divided into young numbers and old numbers.

Therefore, to be exact, the numbers in this column are in parentheses. R1, R2- in the left column means the number of the point where the insulation test is performed, V5. Vll... shows the number of the check point where the continuity test is performed, and C4, C7... shows the number of the check point where the continuity test is also performed. In the table, Xl, X5-. indicate the numbers at points where only from set is performed.

R1, R5-... mean point 1 and an instruction to perform an insulation test. Therefore, head location 1.
When looking down in column 2, fix the head to area (1), and when move the head to area (2),
First, a test is performed on area (2). The contents of the check are eight items from X1 to R1 to R9. At this time, it is necessary to perform a from set, insulation test, and continuity test for each point. The current head location is the youngest. In the case of the oldest number 3, if a continuity test is performed with the from set at the R1 instruction and the V from the 5th instruction at the 5 instruction, it will be found to be defective, so this area is shown surrounded by a square. Next, if we conduct a continuity test with No. 11 at the Vll instruction, it will be found to be defective, so this point is surrounded by a square. In this column, C
15 also has an error, so there are three error displays at the bottom of the program, and one display, like 1-5, indicates a disconnection.

The other head locations are processed in the same way. In the error display column, a + display such as 15 + 16 indicates a short circuit.

When a test is executed using a program created in this way, it does not test all pins, it does not test blank fields, and the from set display does not perform continuity or insulation tests, so it can be completed in an extremely short time with just the from set. . For example, a fromset takes about 100 μsec, and a continuity test takes 1 to 10 msec, so if there are many fromsets, it can be done in a short time. Regarding the program shown in FIG. 4, the number of pins is 17, and in the left column, instructions are given to pin 5 for the insulation test and to pin 12 for the continuity test. For the entire back, the insulation test is 26, the continuity test is 12, and the from set is 102.

[Effects of the Invention] Thus, according to the present invention, conduction and
When performing an insulation test, instead of testing all bottles, it is better to perform the test by executing the above-mentioned means, especially by a program (then it can be processed in a short time and the equipment can be saved). This has the effect of lowering the price.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing the principle configuration of the present invention, Fig. 2 is an operation flowchart of an embodiment, Fig. 3 is an example of a printed wiring board to be tested, and Fig. 4 is an example of a test program for Fig. 3. It is a diagram. 1--Printed wiring board 2--Circuit pattern 3--Dividing head 4--Contact pin 5--Test/judgment section 6--Continuity test means 7--Insulation test means Patent applicant Fujitsu Co., Ltd. Agent Patent Attorney Eisuke Suzuki GP*I Distribution Tomimoto - Figure 1

Claims (1)

[Claims] Pressing the grid-shaped contact pins (4) provided on the dividing head (3) onto the circuit pattern (2) of the printed wiring board (1),
In a wiring test method that inspects the connection of a circuit pattern when a test voltage is applied while being switched by a switching circuit, the test/judgment section (5) uses the from address immediately before applying the test voltage to the contact pin (4). (6), which does not perform a continuity test when outside the head area, but performs a test only at the first head access when inside the head area; , means (7) for determining the oldest numbered point, performing the insulation test at that point, and not performing the insulation test on the smallest numbered head.