JPH0792190A - Inspection equipment for printed board - Google Patents

Abstract

PURPOSE:To enhance the workability by simplifying the inspecting section while eliminating the need of a highly accurate intricate carrying/positioning mechanism. CONSTITUTION:The surface and rear images of a printed board P are picked up by means of cameras 7 disposed above and below a belt conveyor at a substrate measuring section. The positional shift of a measuring pattern from the drilling position of a through hole is then determined based on the positional relationship between a pair of measuring through holes and the positional relationship between a pair of measuring patterns and the positions of upper and lower inspection heads 22, 23 are corrected depending on the positional shift thus determined. The printed board P is then carried to the inspecting position of belt conveyor 5a-5d and transferred from the carrying belt onto a guide board 24 having guide pins being fitted into the guide holes of the printed board P. Subsequently, the guide board 24 lowers and comes into contact with the lower inspection head 23 with the probe penetrating the head and then the upper inspection head 22 lowers thus inspecting the surface and rear of the printed board P.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printed circuit board inspecting apparatus, and more particularly, to an image measurement of a circuit pattern of a circuit board in advance to obtain a positional deviation amount, and based on this positional deviation amount, the inspection head and the printed circuit board are separated. The present invention relates to an apparatus that adjusts a positional relationship and electrically inspects a substrate.

[0002]

2. Description of the Related Art Conventionally, as an apparatus for electrically inspecting a circuit pattern of a printed circuit board, the printed circuit board is conveyed from a substrate storage section to a substrate inspection section by a conveyor, and after the printed circuit board is carried into an inspection position, for example, Generally, the amount of displacement of the circuit pattern on the surface of the printed circuit board is measured with a camera, etc., the position of the printed circuit board is adjusted based on this amount of displacement, and the printed circuit board is positioned at a regular position. Is. Then, the inspection head is brought into contact with the positioned substrate surface, a continuity test or the like is performed, and when the inspection of the substrate is completed, the printed circuit board is unloaded from the inspection unit, and the non-defective product storage unit or the defective product storage unit is sent depending on the inspection result. Will be sorted and stored.

[0003]

However, in the above-described conventional inspection apparatus, since the pattern deviation of the substrate is measured in the substrate inspection unit, the periphery of the inspection unit is complicated by the measuring device such as the measuring camera. Therefore, there is a problem that it is difficult to replace the inspection head, and to perform maintenance and repair. Therefore, a method may be considered in which the board measuring unit and the board inspecting unit are provided in different places, the pattern measuring amount is measured in the board measuring unit, and then the printed circuit board is conveyed to the board inspecting unit for inspection. However, in this case, it is difficult to position the board because the relationship between the measurement position of the printed circuit board and the inspection position of the printed circuit board must be exactly the same. There is a problem in that a precise conveyance / positioning mechanism is required. Therefore, the present invention is to solve the above problems,
The problem is an automatic inspection device in which a board measurement unit and a board inspection unit are separately provided, and it is possible to perform an accurate inspection of a printed circuit board without the need for a complicated and highly accurate transfer / positioning mechanism. To get the right technology.

[0004]

Means for Solving the Problems The measures taken by the present invention in order to solve the above-mentioned problems are a pattern deviation measuring means for measuring a positional deviation amount of a circuit pattern in a substrate measuring section,
An inspection head attached to the printed circuit board arranged in the printed circuit board so that its position can be adjusted, and the pattern displacement measuring means is provided with a board guide hole formed in the printed board or with a predetermined positional relationship with the board guide hole. The positional relationship between at least a pair of through-holes, which are measurement reference holes or board circuit holes, and the circuit pattern formed on the printed circuit board, or at least a pair of reference patterns formed with a predetermined positional relationship therewith. It is a means for comparing the positional relationship between the pattern parts to obtain the positional displacement amount of the pattern part with respect to the through hole, and the board inspection part is provided with a guide pin that fits into the board guide hole. A guide plate for positioning the substrate at the substrate inspection position and a control means for adjusting the position of the inspection head based on the amount of displacement.

In this case, the pattern shift measuring means is used to set the X component, Y component and θ of the position shift amount on the printed circuit board.
As a means for obtaining the component, the control means controls the position of the inspection head with respect to the set position by the X component, the Y component, and the θ component of the displacement amount.
It is desirable that the composition is modified so as to be modified.

Further, it is desirable that the guide plate is mounted so as to be movable between a carry-in position of the printed circuit board in the circuit board inspection section and a contact position of the printed circuit board with respect to the inspection head. Furthermore, the probe of the inspection head is attached to the guide plate. It is preferable to provide a probe guide hole through which

The above-mentioned conveying means is composed of a pair of conveying belts arranged in parallel with each other along the conveying direction, and the conveying belts are held at intervals for supporting both edges of the printed circuit board and are respectively arranged in the conveying direction. It is desirable that the support be rotatably supported about an axis extending in the direction such that the interval between the transport bands can be expanded by the rotation of each transport band.

[0008]

According to such means, the positional deviation amount of the circuit pattern is measured with reference to the through hole of the printed board in the board measuring section, and the board guide hole of the printed board is used as the guide pin of the guide board in the board inspecting section. Since they are fitted and positioned, if the position of the inspection head is corrected based on the amount of displacement, the substrate can be inspected accurately. Therefore, the accuracy of the transport mechanism from the board measuring unit to the board inspecting unit and the positioning mechanism of the printed circuit board in the board inspecting unit is not required to be accurate, and in particular, the mechanism around the board inspecting unit can be simplified.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment of a printed circuit board inspection device according to the present invention will be described with reference to the accompanying drawings. As shown in FIG. 1A, in this embodiment, a loader A in which a pre-inspection printed circuit board P is stacked on a vertically movable substrate support 2 in the lower portion of a frame 1 and a post-inspection printed circuit board are provided. The unloader B for accommodating non-defective products by stacking them on the substrate support 3 and storing the defective products among the printed boards after the inspection on the substrate support 4
Unloaders C that are stacked on top of each other and housed are arranged.

Belt conveyors 5a, 5b, 5c and 5d are continuously arranged above the loaders A, unloaders B and C, and a pair of drive motors for moving the conveyor belts are provided on each belt conveyor. A board stopping mechanism (which includes a board stopper rotatably mounted and a drive cylinder for rotating the board stopper) for stopping the conveyed printed board at a predetermined position, and a pair of carrying belts downward. And a turning mechanism for turning.

FIG. 1B shows a rotating mechanism of the transfer conveyor 5a, and the other transfer conveyors 5b, 5c, 5d have the same structure. Support beam 1 mounted on frame 1
A rotary shaft 16 is rotatably supported with respect to 1 in the transport direction. The rotating arm 12 is fixed to the rotating shaft 16, and the conveyor support plate 13 is fixed to the tip of the rotating arm 12. The conveyor guide plate 13 includes an upper guide roller 14
The lower guide roller 15 is rotatably supported, and the conveyor belt 10 is installed over them. Each of the belt conveyors is provided with two of the above structures, and a pair of conveyor belts 10
Are arranged to face each other to support both ends of the printed circuit board P.

The link 17 is fixed to the rotary shaft 16, and the driving member 1 is provided by an engaging shaft 18a fitted in a loose hole 17a thereof.
8 is connected. The drive member 18 is fixed to a piston rod 19 of an air cylinder (not shown). When the air cylinder is operated to project the piston rod 19 and the drive member 18 to the right, the rotary arm 12 rotates clockwise through the rotary shaft 16, and the transport mechanism including the transport belt 10 also rotates clockwise. Move.

Therefore, the distance between the conveyor belt 10 and the other conveyor belt 10 (not shown) is increased, and the printed circuit board P can be moved up and down by passing between the conveyor belts. The mutual distance between the conveyor belts 10 and 10 can be changed by a distance adjusting mechanism (not shown) including a screw rod screwed into the support beam 11 and a pulse motor for rotating the screw rod.

The transfer hand 6 shown in FIG. 1 descends between the above-mentioned conveyor belts 10 and adsorbs the printed circuit board P stored in the loader A, and rotates to convey it with a wider space. Belt conveyor 5 passing between belts 10 and 10
Ascend to the top of a. Here, after the conveyor belts 10 and 10 have returned to the normal state and the interval has been narrowed, the transfer hand 6 releases the printed circuit board P and places it on the conveyor belts 10 and 10, and the belt conveyor 5a is activated. The printed circuit board P is conveyed rightward.

A substrate stopper 8 shown in FIG. 2 is rotatably supported on a rotary shaft 16 at the right end of the belt conveyor 5a, and is rotated by an air cylinder (not shown) to descend from above onto the conveying surface. It is supposed to do. Printed circuit board P
When comes into contact with the substrate stopper 8 on the conveyance surface, the belt conveyor 5a is stopped by the optical substrate sensor 30 built in the substrate stopper 8. This position is the substrate measurement position.

Above and below the substrate measuring position, XY is provided.
Imaging cameras 7a and 7b supported by a driving mechanism are provided, and images the upper and lower surfaces of the printed circuit board P in parallel. Here, on the printed circuit board P, as shown in FIG.
Four substrates guide holes _{Q 1, Q 2, Q 3} , Q 4 is bored is bored through holes R _1, R ₂ and a through hole for other circuits for simultaneously measured. The measurement through holes R _{1 and} R ₂ may also serve as circuit through holes. Moreover, the measurement patterns S _{1 and} S ₂ and a circuit pattern (not shown) are simultaneously formed on both upper and lower surfaces of the printed circuit board P. The measurement patterns S _{1 and} S ₂ may also serve as circuit patterns.

FIG. 3 shows a method of measuring the pattern shift of the substrate by the image pickup cameras 7a and 7b. The calculation in the following measurement is performed by the computer 9 shown in FIG. When the printed circuit board P comes into contact with the substrate stoppers 8a and 8b, the substrate sensor 30 detects this and the imaging cameras 7a and 7b are moved to the alignment mark 1 including the measurement through hole R ₁ and the measurement pattern S ₁ shown in FIG. Move to the shooting position of.

The reference center coordinates (AX1, AY1) of the alignment mark 1 are preset and stored and held. In the image photographed at this position, the portion of the measurement pattern S ₁ having a high reflectance becomes a white pixel, and the gravity center position gw1 = (gw1x, gw1y) of this white pixel area is detected. On the other hand, the portion of the measurement through hole R _{1 where} the reflected light cannot be obtained becomes a black pixel, and the gravity center position gb1 = (gb1x, gb1y) of this black pixel area is detected.

When the processing of the alignment mark 1 is completed, the image pickup cameras 7a and 7b are moved to the image pickup position of the alignment mark 2 composed of the measurement through hole R ₂ and the measurement pattern S ₂ of FIG. Here, the reference center coordinates (AX2, AY2) of the alignment mark 2 are preset and stored and held. Also for the image photographed at this position, the center of gravity position g of the measurement pattern S ₂ is the same as above.
w2 = (gw2x, gw2y) and the center of gravity gb2 = (gb2x, gb2y) of the measuring through hole R ₂ are detected.

From the above results, the difference in coordinates at each alignment mark is calculated as g1x = gw1x-gb1x, g2x = gw2.
x-gw2x g1y = gw1y-gb1y, g2y = gw2
y-gw2y AX = AX2-AX1, AY = AY2-
AY1 gwx = gw2x-gw1x, gwy = gw2
y-gw1y, and the positional displacement amount of the pattern is calculated as follows.

ΔX = (g1x + g2x) / 2 ΔY = (g1y + g2y) / 2 Δθ = KK-WK KK = tan
⁻¹ (AX / AY) WK = tan ⁻¹ (gwx / gwy) Further, the deviation amount Δθ in the angular direction may be obtained as follows. Δθ = BK-WK BK = tan
^-1 (gbx / gby) (gbx = gb2x-gb1x, gby = gb2y-g
b1x)

In this way, the amount of deviation of the measurement pattern in the X, Y, and θ directions from the measurement through hole can be obtained from the image of the camera. The measurement pattern is formed at the same time as the circuit pattern, or also serves as a part of the circuit pattern,
On the other hand, the measurement through hole (which may also be used as a circuit through hole) is formed at the same time as the board guide holes Q _1, Q _2, Q _3, Q ₄ or also as the board guide hole itself. There is. Therefore, the displacement amount can be used as the displacement amount of the circuit pattern with respect to the substrate guide hole.

When the positional shift amount of the circuit pattern is obtained, the substrate stopper 8 is rotated upward to be disengaged from the printed substrate P, and the belt conveyors 5a and 5b are activated. The printed circuit board P is transferred from the belt conveyor 5a shown in FIG. 1 to the belt conveyor 5b and is carried into the board inspection unit 20. When the printed circuit board P comes directly under the inspection press 21, it comes into contact with the same substrate stopper 27 as described above, and the same substrate sensor (not shown) as described above causes the belt conveyors 5a and 5b.
Stops. This position is the substrate inspection position.

The board inspecting section 20 includes an upper inspecting head 22 mounted so as to be able to move up and down by the inspecting press 21 and a lower inspecting head 2 provided below the belt conveyor 5b.
3 and a guide plate 24 that is vertically movable between the upper inspection head 22 and the lower inspection head 23. As shown in FIG. 4, the upper inspection head 22 is
An XYθ table 22a attached to the press drive unit,
A probe plate 22b fixed to the lower surface of the XYθ table 22a, a probe 22c planted in a predetermined pattern on the lower surface of the probe plate 22b, and a probe hole (not shown) penetrating the probe 22c in a loosely fitted state. And a guide plate 22d provided with.

The lower inspection head 23 has an XYθ table 23a installed at the bottom of the frame, a probe plate 23b fixed to the upper surface of the XYθ table 23a, and a probe planted on the upper surface of the probe plate 23b in a predetermined pattern. 23c. Guide plate 24 includes a substrate guide hole _{Q 1, Q 2, Q 3} , embedded in positions corresponding to Q ₄ are tip conical four guide pins 24a of the printed board P, the probe 23
It is provided with a probe hole (not shown) formed corresponding to the formation position of c, and is moved up and down along the guide rod 25 by an air cylinder (not shown).

[0026] printed circuit board P is stopped at the substrate inspection position, the guide plate 24 is raised to between the conveyor belt of the belt conveyor 5b, the guide pin 24a directly below the substrate guide hole _{Q 1, Q 2, Q 3} , Q 4 Stops at the position where is placed. Then, the conveyor belt opens downward as described above to widen the distance between the conveyor belts, so that the printed circuit board P drops onto the guide plate 24 and is guided to the board guide holes Q _1, Q _2, Q _3, Q ₄ . The pin 24a is fitted and positioned.

Then, the guide plate 24 is lowered with the printed circuit board P placed thereon, the probe 23c of the lower inspection head 23 is introduced into the probe hole, and the lower surface of the printed circuit board P is brought into contact with the probe 23c. Next, the upper inspection head 2
2 descends to bring the probe 22c into contact with the upper surface of the printed board P. Inspection head 2 with printed circuit board P above and below
When it is sandwiched between 2, 23, the inspection program is executed by the inspection computer 26 shown in FIG. 1, and the open / short check of the circuit patterns formed on the upper and lower surfaces of the printed circuit board P is performed.

When the inspection of the circuit pattern is completed, the upper inspection head 22 rises and then the guide plate 24 rises.
Then, when the guide plate 24 is lifted up between the conveyor belts,
The conveyor belt rotates upward and supports both edges of the printed circuit board P. After that, the printed circuit board P is conveyed on the belt conveyor 5b and transferred to the belt conveyor 5c. The printed circuit board P that has passed the circuit pattern inspection is stopped by the substrate stopper 28, the conveyor belt of the belt conveyor 5c opens and falls, and is accommodated in the unloader B. The printed circuit board P determined to be defective as a result of the inspection is further transferred to the belt conveyor 5d, stopped by the substrate stopper 29, and then stored in the unloader C from there.

As described above in detail, in this embodiment, the positional deviation amount of the circuit pattern is obtained with reference to the position of the measurement through hole which is formed at the same time as the substrate guide hole of the printed circuit board and has a predetermined positional relationship. Since the position of the inspection head is corrected based on this amount of positional deviation, it is only necessary to position the printed circuit board by the board guide hole with respect to the circuit board inspection section, and the accuracy of the printed board transfer mechanism and the board inspection section positioning mechanism can be improved. It is possible to perform an accurate board inspection without requiring the use of a simple transfer mechanism and a positioning mechanism.

For the same reason as above, the board measuring section and the board inspecting section can be provided at different positions, and the accuracy of the inspecting position does not depend on the distance between them, so that a free layout is possible. . For these reasons, the structure of the board inspecting unit is simplified, and the work of replacing, inspecting, and maintaining the inspection head and the like becomes easy. Furthermore, since the board measuring unit, the transport mechanism, and the like can be simplified, the manufacturing cost and the size of the entire inspection apparatus can be reduced.

As for the positional deviation amount of the circuit pattern on the printed circuit board, the deviation amount in the X, Y and θ directions is calculated from the pair of measuring through holes and the measuring pattern, and the position of the inspection head is calculated based on each deviation amount. Since the correction is performed, it is possible to accurately cope with any positional deviation of the circuit pattern.
Since the guide plate is movable between the loading position of the substrate and the contact position of the substrate with respect to the inspection head, it is possible to simplify the inspection mechanism by using the guide plate itself as a means for transporting the printed circuit board in the substrate inspection unit. At the same time, the moving mechanism of the lower inspection head becomes unnecessary.

Since the guide plate has the probe hole, it also serves as the guide plate of the lower inspection head, and simultaneous inspection of both surfaces of the substrate is possible with a simple structure. In the belt conveyor, since the distance between the conveyor belts is variable, the printed circuit board can be moved up and down through the conveyor belts, and the device can be downsized.
Since the conveyor is opened and closed by the rotating operation, only a small operation space is required, and the degree of freedom of arrangement of the peripheral mechanism is improved.

[0033]

As described above, according to the present invention,
High-precision board without increasing the precision of the transfer mechanism and positioning mechanism for the printed circuit board, because the pattern displacement is measured by the board measuring section located at a position different from the board inspection section with reference to the through hole of the board. An inspection can be done. Also, the structure of the board inspection unit can be simplified, and the inspection heads can be replaced,
Maintenance work becomes easy.

[Brief description of drawings]

FIG. 1 is a schematic view (a) showing an overall configuration of a printed circuit board inspection apparatus according to the present invention, and an enlarged cross-sectional view showing a structure of a conveyance unit of the inspection apparatus.

FIG. 2 is a plan view showing an example of a printed circuit board measured by the inspection apparatus.

FIG. 3 is a flowchart showing a method of calculating a pattern positional deviation amount in a substrate measuring unit of the inspection apparatus.

FIG. 4 is an enlarged explanatory view showing details around a board inspection unit of the inspection apparatus.

[Explanation of symbols]

5a, 5b, 5c, 5d belt conveyor 7a, 7b imaging camera 10 conveyor belt 22 the upper inspection head 22a, 23a XY.theta. Table 23 below inspection head 24 a guide plate 24a guiding the pin P PCB _{Q 1, Q 2, Q 3} , Q 4 Board guide hole S _1, S ₂ measurement pattern R _1, R ₂ measurement through hole

Claims (5)

[Claims] 1. A board measuring section for inputting a surface image of the printed board to measure the printed board, a board inspecting section for electrically inspecting a circuit pattern of the printed board, and a board for measuring the board. A printed circuit board inspecting device having a conveyance means for conveying a printed circuit board to an inspection section, wherein a pattern deviation measuring means for measuring a positional deviation amount of the circuit pattern in the board measuring section and a print arranged in the board inspection section. An inspection head mounted so that its position can be adjusted with respect to the board; and the pattern shift measuring means is a board guide hole formed in the printed board or a measurement reference hole formed in a predetermined positional relationship with the board guide hole. Alternatively, the positional relationship between at least a pair of through holes, which are circuit board holes, and the circuit pattern formed on the printed circuit board or a predetermined position between the circuit pattern and the circuit pattern. Is a means for comparing the positional relationship between at least a pair of pattern portions, which is a reference pattern formed by the relationship, and obtaining the amount of positional deviation of the pattern portion with respect to the through hole. A guide plate for fitting the guide hole in the guide hole; a guide plate for positioning the printed circuit board at a substrate inspection position by the guide pin; and a control means for adjusting the position of the inspection head based on the displacement amount. Printed circuit board inspection device. 2. The pattern shift measuring means according to claim 1, wherein the pattern shift measuring means is a means for obtaining an X component, a Y component and a θ component of the positional shift amount on the printed circuit board, and the control means is a position of the inspection head. Is an apparatus for inspecting a printed circuit board, which is configured to correct the position deviation with respect to the set position by the X component, the Y component, and the θ component. 3. The print according to claim 1, wherein the guide plate is movably attached between a loading position of the printed board in the board inspection unit and a contact position of the printed board with the inspection head. Board inspection device. 4. The printed circuit board inspection apparatus according to claim 3, wherein the guide plate has a probe guide hole through which a probe of the inspection head is passed. 5. The conveying means according to claim 1, wherein the conveying means comprises a pair of conveying belts arranged in parallel with each other along a conveying direction, and the conveying belts are arranged at intervals for supporting both edges of the printed circuit board. An inspection device for a printed circuit board, which is held and rotatably supported around an axis extending in the transport direction, and is configured to expand the interval between the transport bands by the rotation of each transport band.