JPH0116053Y2 - - Google Patents

Description

[Detailed description of the invention] This invention relates to the improvement of printed circuit board inspection equipment.
The main purpose is to obtain a printed circuit board inspection device that can improve the reliability of inspection by taking into account the warping of printed circuit boards that have already been wired, and the secondary purpose is to realize such a device at a low cost. That is.

This type of inspection device is not limited to this type, but after wiring is completed, test pins provided corresponding to multiple test patterns provided on the printed circuit board are brought into conductive contact at the same time, and the printed circuit board is operated. As a state, input/output signals are tested at one time.

This device includes a group of test pin units arranged according to the distribution of test points on the printed pattern. This test pin unit has a structure as shown in FIG.

This test pin unit includes a flange-shaped guide sleeve 2 that guides the pointed test pin 1 in its axial direction, and a transparent guide sleeve 2 that guides the pointed test pin 1 at a predetermined location on the test base 3, that is, a position corresponding to the test point on the printed circuit board. A fixing sleeve 5 for fixing to the hole 4, a threaded portion 6 provided on the unflangeed end side of the guide sleeve 2, and a locking portion 7 at the other end of the inspection pin 1 are suspended between. A coil spring 8 is provided, and the inspection pin 1 is pressed against the printed circuit board by the biasing force of the coil spring during inspection.

An inspection apparatus equipped with such an inspection unit functions particularly well when the printed circuit board does not appear to be warped.

However, with paper epoxy printed circuit boards, etc., when the soldering wiring is completed by an automatic soldering device after parts are inserted, the wiring pattern side generally shrinks, and in extreme cases, the printed circuit board P will shrink as shown in Figure 2. It is unavoidable that warpage like this will occur. This warpage depends on the fiber distribution of the substrate epoxy and the shape of the substrate and is not uniform.

If we consider the case where such a printed circuit board 9 is fixed at both ends as schematically shown in FIG. Inspection pin unit u...
Since the stress applied to the test pins varies depending on the position of the unit, the contact force of the test pins to the test points differs significantly between the central and peripheral parts of the printed circuit board 9. The unavoidable disadvantage is that the pressure is not secured, the reliability of contact varies, and the reliability of inspection is greatly reduced.

In order to eliminate such defects, test pins 1,
It is conceivable to adjust the amount of protrusion of 1...1 with respect to the inspection base A in the range of _l1 to _l2 .

As an example, as shown by the dashed line in FIG. 1, the flange 9 of the guide sleeve 2 and the inspection base 3
It is conceivable to insert an intermediate sleeve 10 (or a pedestal) to ensure the necessary amount of protrusion between the two.

However, it is not only inefficient to find the necessary intermediate sleeve 10 individually according to the arrangement of the inspection pin unit to ensure the protrusion amount of each inspection pin, but also to prepare a large number of intermediate sleeves of different lengths. have to do so, resulting in higher costs.

The present invention was developed in view of this point. The details of the present invention will be explained below with reference to the embodiment shown in FIG.

In this embodiment, the inspection pin 1 is pointed at its inner periphery.
A threaded groove 22 is uniformly cut on the outer periphery of a flanged cylindrical guide sleeve 12 that guides the guide sleeve 1 slidably in the axial direction. The outer periphery of the guide sleeve 12 is fitted so as to be slidable in the axial direction along the inner periphery of a fixed sleeve 15 that is fitted and fixed in the through hole 14 of the inspection base 13. One end of the coil spring 18 is locked and fixed to a locking member 17 provided on the cylindrical end side of the inspection pin 11. The other end of the coil spring 18 is screwed into a threaded groove 22 provided on the outer periphery of the guide sleeve 15, and the inspection pin 11 is held in a sharp position. Fix it so that it can be biased toward the head.

The collar 19 of the guide sleeve 12 and the inspection base 13
A nut 20 is screwed into a threaded groove 22 on the outer periphery of the sleeve, and the relative position of the guide sleeve 12 with respect to the inspection base 13, that is, the amount of protrusion, can be finely adjusted according to the position of the nut 20. There is.

In particular, if the engagement relationship between the nut 20 and the fixed sleeve 15 is configured such that the nut is restricted only in the axial direction, the nut 20 is immovable, and can freely move only in the rotational direction, the inspection pin 11 Inadvertent displacement of each inspection unit in the axial direction can be prevented even when no urging force is applied to the printed circuit board during inspection.

The test pin unit having such a configuration is fixed to a predetermined position on the test base, that is, to the through hole 14 drilled at the position where the test point (pattern) is arranged on the printed circuit board, and Adjust the nut 20 of each inspection pin unit according to the
If you determine the height of the guide sleeve from the inspection base by holding the flange 19 so that it does not rotate with your fingers, etc. and screwing it into the thread groove on the outer periphery of the guide sleeve, you can easily adjust the height of each inspection unit during inspection. The test pins contact the test points with equal pressure, ensuring uniform contact pressure and improving test reliability.
Furthermore, compared to methods such as using a vacuum suction or press device to inspect the printed circuit board while minimizing warpage, it is possible to realize a lower cost and more reliable inspection device. In addition, independent of adjusting the height of the guide sleeve from the inspection base, by changing the length of the part of the coil spring that acts as a spring, the pressure that contacts the test point relative to the amount of pushing of the inspection pin can be adjusted. The optimum contact force can be easily set.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of the main parts of this type of inspection unit, Fig. 2 is a schematic diagram showing the degree of warpage of a printed circuit board after soldering, Fig. 3 is a schematic diagram showing the pattern of inspection of a printed circuit board, and Fig. 4 is a side view of the inspection device of the present invention,
FIG. 5 is a side view of the main part of the inspection pin unit used in the device of the present invention. u...Inspection pin unit, 11...Inspection pin, 12
...Guide sleeve, 13...Inspection base, 18...Coil spring, 20...Nut.

Claims (1)

[Claim for Utility Model Registration] A threaded groove is provided on the outer periphery of a flanged cylindrical guide sleeve that guides the pointed inspection pin in the axial direction on the inner circumferential surface, and this guide sleeve can freely slide in the direction perpendicular to the inspection base. An inspection pin unit configured to attach to the inspection pin and insert a coil spring between the other end of the inspection pin and the other end of the guide sleeve to apply a biasing force in the direction of the tip of the inspection pin is placed on an inspection base. In the printed circuit board inspection apparatus, a nut is disposed on the upper surface of the inspection base to be screwed into the thread groove on the outer periphery of the guide sleeve in order to adjust the protrusion amount of the pointed inspection pin, and A printed circuit board inspection device characterized in that the coil spring is screwed into the thread groove to adjust the force.