JPS61221680A - Automatic inspecting device for printed circuit board - Google Patents

Abstract

PURPOSE:To improve inspection efficiency by providing a sheet which varies color density when applied with a voltage in contact with a printed wiring board and knowing the position of a defective part with ease. CONSTITUTION:An electrochromic element sheet (ECD) 12 and an electrode are provided while sandwiched between a printed board 1 and a base 10. If a defective part is found by inspecting the printed wiring board 1, a voltage is applied between an inspection probe 3 and the electrode 13. Then, the ECD 12 colors with the voltage and varies in color density with the applied voltage, so the voltage is made different between a short-circuit defect and an open fault to vary the density of a color, thereby easily discriminating both faults Further, the voltage applied to the ECD 12 is about 1V or low and when the inspection voltage of the wiring board 1 is hither than it, the voltage is switched to a display voltage for the ECD 12. Further, the ECD 12 is applied with the voltage reversely and then discolored, so the ECD can be used repeatedly.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to an automatic testing device (hereinafter referred to as bare board tester) for testing printed circuit boards (printed wiring boards).

[Background and current issues]

There is a circular conductive part with a hole called land (2) that connects the front and back printed circuits. A bare board tester is a device that tests continuity or non-continuity between the lands (2) by applying voltage. As shown in FIG. 4, the bare board tester has a test probe (3) with a spring action mounted on a test head (4) in alignment with the land (2) of the printed wiring board (1). As shown in Figure 4 (b), when the printed wiring board (1) is placed on the test probe (3), the tip will come into contact with the land (2) and the test probe and land
Conduct. By applying a voltage to one of the test probes and testing whether voltage is applied to the remaining test probes, data between conductive lands can be obtained.

In FIG. 5, the inspection probe (3) is connected to the inspection head (4).
) and through the wiring (8) to the terminal (6) of the switch circuit section (5). The switch circuit section (5) applies voltage to the test probe (3) and detects the voltage applied to the test probe (3). (9) is a pressurizing machine for bringing the printed wiring board (1) above the zero value into close contact with the inspection head (4). Information detected by the test probe (3) is transmitted to the test circuit (7), where it is compared with connection information of a non-defective product, and the number of the test probe with the defective connection is output and displayed on a printer or CRT (not shown).

The number of the inspection probe is 0, which is the number of the terminal (6) of the switch circuit. Therefore, in order to know the defective location of the printed wiring board (1), a layout diagram of the probe number αυ as shown in FIG. 6 is required. For example, the display of the defective part is “8HORT 25
-2JOPBN 10-14" etc. is output. This means that the 25th and 26th bins are short-circuited, and the 10th and 14th bins are short-circuited.
This means that the numbered bottle has failed to open. In order to confirm or correct these defective locations, it is necessary to know their locations from the above-mentioned layout diagram, but when the number of pins is large, it takes time and effort to find the defective locations.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide an automatic inspection machine that displays defective circuits on a printed wiring board in an easy-to-understand manner and performs efficient inspection.

[Summary of the invention]

In order to achieve the above object, the present invention provides an apparatus for applying a voltage to a conductive part of a printed wiring board to determine whether a wiring circuit is normal or abnormal. This is an automatic printed circuit board inspection device that uses sheets with varying color densities to display defective parts of the printed wiring board at positions corresponding to the actual printed wiring boards for efficient inspection.

[Embodiments of the invention]

FIG. 1 shows the construction of the main parts of an embodiment of a bare board tester according to the present invention. The feature of the present invention is that a solid-state electrochromic device sheet (hereinafter referred to as ECD) is placed between the printed circuit board (1) and the stand α, and the electrode α
It was set up to hold the seagull between them.

After the inspection of the printed wiring board is completed, if there is a defective part, the inspection probe (3) of the defective part is found.
) and the electrode (131. ECD α is more colored than voltage 1. For example, probe number αυ in Figure 6
When voltage is applied to No. 10, No. 14, No. 25, and No. 26, R
As shown in Figure s2 in OD (13), those lands and patterns develop color. ECDα2 has a memory property, so even if the voltage is set to zero and taken out, the pattern in Figure 2 remains. Compare this pattern with the wiring board. In C2, defective parts can be found more easily.

As shown in FIG. 3, the BCD α area changes the color density by applying two voltages, so it is possible to change the voltage and change the color density to make it easier to distinguish between short-circuit failures and open-circuit failures.

The applied voltage of FiCDα is as low as about 1 V, and when the test voltage of the printed wiring board is higher than that, the display voltage C is switched by BCDα2.

% No. 10, pages 48 to 51, all-solid-state electrochromic device) [Effects of the Invention] According to the present invention, after conducting a continuity test on a printed wiring board using an inspection probe, it is possible to identify defective parts of the printed wiring board. Since the position C2 corresponding to the printed circuit board is shown, the position of the defective part can be easily known, and an automatic printed circuit board inspection apparatus with high inspection efficiency can be obtained.

[Brief explanation of drawings]

Fig. 1 is an embodiment of the bare board tester according to the present invention, and is a block diagram of the main parts. Fig. 2 is a diagram showing an example of the display according to ECDα2C of the above embodiment. Fig. 3 is the voltage-transmittance characteristic of BCDα. 4 is a structural diagram of the inspection section of a conventional bare board tester, FIG. 5 is a configuration diagram of a conventional bare board tester, and FIG. 6 is a diagram showing the number arrangement of the inspection probes (13).
- 1... Printed wiring board 2... Land 3... Inspection probe 4... Inspection head 5... Switch circuit section 6... Switch circuit terminal 7... Inspection circuit
8... Wiring 9... Pressure machine 10
... Stand 11 ... Probe number 12 ... ECD (solid-state Nire chromic device sheet) 13 ... Electrode (7317) Agent Patent attorney Noriyuki Chika (and 1 others)
Name) 2nd figure, figure 4, figure 5, figure 6

Claims (1)

[Claims] In a device that applies a voltage to a conductive part of a printed wiring board to determine whether a wiring circuit is normal or abnormal, a sheet is provided in close contact with the printed wiring board and whose color density changes depending on the application of voltage. An automatic inspection device for printed circuit boards featuring: