JPH0334803B2 - - Google Patents

Description

[Detailed Description of the Invention] [Summary] This is an apparatus for inspecting irregularities using a light cutting method,
Observing first and second projectors that project first and second narrow bands of light that are tilted in opposite directions and intersect in the middle, and an image illuminated by the first and second narrow bands of light. The unevenness inspection device is improved in performance by being equipped with a means to perform the inspection.

[Industrial application field]

The present invention relates to an unevenness inspection device using a light cutting method, and more particularly to an improvement of a device for inspecting whether electronic components mounted on a wiring board are mounted in the correct posture.

The light cutting method, as is widely known, is a method in which a thin band of light is projected onto a test surface, and the irradiated surface is observed from a direction that is inclined to the projection angle of the thin light to determine the unevenness of the test surface.

This optical cutting method is non-contact and can measure irregularities of several millimeters in height, so it has come to be used in mounted component inspection equipment that automates and inspects the appearance of electronic components mounted on wiring boards. Ta.

[Conventional technology]

FIGS. 5A and 5B are side views showing an outline of the mounted component inspection apparatus according to the prior art.

In Fig. 5A, 1 is a printed board, 2 and 3 are electronic components mounted on the printed board 1, 4 is a thin light strip, and 5 is a microscope. When projected onto the component 2, the bright image irradiated onto the light band 4 is as shown in FIG. The image 2b projected onto the upper surface of the image 1 is observed by the microscope 5 with a deviation from the image 2b.

Therefore, the amount of deviation δ between the projected images 2a and 2b is
This is an amount determined by the height from the top surface of the printed board 1 to the top surface of the electronic component 2 and the intersection angle between the light band 4 and the optical axis of the microscope 5. For example, when the electronic component 2
When the shape of is a cube, by moving the light band 4 or the printed board 1, as shown in FIG. 5A,
There are light bands 4a and 4 at two locations along the length of the electronic component 2.
By irradiating the electronic component 2, the mounting position (tilt) of the electronic component 2 can be determined from the amount of each shift δ at that time.

[Problem that the invention seeks to solve]

However, the various electronic components mounted on the printed circuit board 1 have different heights depending on their type and model. There are cases where another electronic component (hybrid integrated circuit) 3 having a diameter of about 15 mm is mounted, and the electronic component 3 is positioned in the direction in which the light band 4 is to be moved in order to inspect the mounting state of the electronic component 2.

In this case, it may not be possible to irradiate the light band 4b to the edge near the electronic component 3, and in the conventional mounted component inspection apparatus, it is troublesome to rotate the printed board 1 180 degrees and inspect it from a direction where the electronic component 3 does not get in the way. Otherwise, there is a problem that inspection of the mounting state of the electronic component 2 has to be given up, and it has been desired to eliminate this problem in order to ensure the reliability of the printed board 1.

[Means for solving problems]

1A and 1B are diagrams for explaining the basic configuration of the device of the present invention, 11 and 12 are thin light bands, 1
3 indicates an observation means.

As shown in Figure 1A, the above problem is caused by a device that inspects the unevenness of a test surface using a light cutting method that projects a thin band of light onto the test surface. a first projector that projects a light band 11; a first projector that is inclined in the opposite direction to the first narrow light band 11;
A second thin light band 1 intersects with the thin light band 11 of
2; and observation means 13 for observing the test surface illuminated by the first and second thin bands 11 and 12 from above the intersection. Furthermore, a TV camera in which the observation means 13 captures the illuminated image and outputs the image signal, and an image memory in which the image signal is digitized and stored;
The problem is solved by an unevenness inspection apparatus characterized by comprising a control circuit that accesses the image signal and the stored signal.

[Effect]

According to the unevenness inspection device, when the rectangular part 15 is not mounted on the substrate 14, the integral thin bands 11 and 12 of light that intersect at the middle part are two images observed by the observation means 13. become parallel rays. On the other hand, when the rectangular component 15 is mounted on the upper surface of the substrate 14, the light cut image is such that the middle part of the parallel light beam corresponds to the height of the rectangular component 15, as shown in FIG. By shifting inward, the square part 1
You can know the height (unevenness) of 5.

When the rectangular component 15 is mounted without tilting, the deviations δ ₁ , δ ₂ , δ ₃ , and δ ₄ are the same amount, but the tilted narrow band of light is shifted and 2
Compared to devices that project two narrow bands of light that are tilted in the same direction, the device of the present invention is configured to project a pair of thin bands of light that intersect, 11 and 12. Even if there is a high place near the outside of the projection position that would impede unevenness inspection, the height restriction is significantly relaxed.

Therefore, for example, when the present invention is applied to a mounted component inspection device using an optical cutting method, if there is another mounted component near the tested mounted component that is higher than the tested mounted component and cannot be inspected by the conventional device. It is now possible to inspect target parts.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 2 is a side view showing an outline of the application of the present invention to a mounted component inspection device, FIG. 3 is a diagram for explaining a typical observation image using the device, and FIG. 4 is a side view showing the main drive of the device. FIG. 2 is a block diagram equipped with a circuit.

In FIG. 2, in which the same reference numerals are used for parts common to those in FIG.
18 is an electronic component mounted close to the electronic component 17; 19 is a projector consisting of a laser light source 20, a cylindrical lens 21, etc.;
1 and 12 intersect in the middle and project onto the printed board 16, and a TV camera 22 corresponding to the observation means 13 is disposed above the intersection of the light bands 11 and 12.

In the device configured in this way, the pair of light bands 11 and 12 are tilted in opposite directions to the optical axis of the TV camera 22 and projected onto the printed board 16. When the component 17 is correctly mounted and the top surface of the printed board 16 and the top surface of the electronic component 17 are parallel, the TV camera 2
The image taken in _{No. 2} is the same as that _{in FIG} .

On the other hand, when the electronic component 17 is tilted in the left-right direction as shown in FIG _. 3A (the figure is tilted upward to the _left ), as shown in _FIG . Becomes ₄ .

Next, when the electronic component 17 is tilted in the left-front direction as _{shown in FIG .} become.

Furthermore, when the electronic component 23 having a circular cross section is mounted on the printed circuit board 16 in the correct position as shown in FIG. The deviations δ ₅ and δ ₆ have the same value.

Although not shown, when the electronic component 17 is tilted in the left-right direction and the front-back direction,
_The image is _a composite of FIG.

In Fig. 4, in which the same reference numerals are used for parts common to Fig. 2, 24 is an X-Y table, 25 is an A/D
Converter, 26 is an image memory, 27 is a CPU,
A pair of narrow light bands 11 and 12 are projected onto the electronic component 17, and the analog signal of the image taken by the TV camera 22 is converted into a digital signal by the A/D converter 26 and stored in the image memory 26. .

Then, the CPU 27 accesses it and inspects the stored image, that is, measures the deviations δ ₁ to δ ₆ of the light stripes, measures how much they match the reference values, outputs the information, and also checks the mounting of the printed board 16. X-Y
The table is driven so that the next inspection position of the printed board 16 (the next electronic component to be inspected) faces the TV camera 22.

Thereafter, the above-mentioned operations are repeated to automatically complete the inspection of all the locations necessary for inspecting the printed board 16.

〔Effect of the invention〕

As explained above, according to the present invention, the light band 11 from the right side on which the tall electronic component 18 is mounted
is projected to the left side of the electronic component 17, and since the light band 12 from the left side is projected to the right side of the electronic component 17,
Just as it is possible to observe the mounted state of the electronic component 17 without being obstructed by the electronic component 18, which was an obstacle in the conventional device, even if there is an obstacle near the uneven inspection position and higher than the inspection position, the obstacle can be easily observed. Since the height restriction can be relaxed compared to conventional devices, the unevenness inspection device has the effect of improving its performance.

[Brief explanation of drawings]

Figures 1A and 2B are diagrams for explaining the basic configuration of the device of the present invention, Figure 2 is a side view showing an outline of the application of the present invention to a mounted component inspection device, and Figure 3 is a representative example of the device using the device. A diagram to explain the target observation image,
FIG. 4 is a block diagram showing the apparatus equipped with the main driving circuit, and FIGS. 5A and 5B are side views showing an outline of the conventional mounted component inspection apparatus. In the figure, 11 and 12 are thin bands of light, and 13
1 is an observation means, 16 is a printed board, 17 and 18 are electronic components, 19 is a floodlight, 22 is a TV camera, 24
25 is an A/D converter, 26 is an image memory, and 27 is a CPU (control circuit).

Claims (1)

[Claims] 1. In an apparatus for inspecting the unevenness of a test surface by a light cutting method in which a narrow band of light is projected onto the test surface, a first narrow band of light 11 is projected onto the test surface at an appropriate inclination angle. a first light projector that projects a second light band 12 that is inclined in the opposite direction to the first narrow light band 11 and that intersects the first narrow light band 11; An unevenness inspection apparatus comprising: a projector; and an observation means 13 for observing the test surface illuminated by the first and second narrow light bands 11 and 12 from above the intersection. 2. A TV camera through which the observation means 13 images the illuminated image and outputs the image signal; an image memory that digitizes and stores the image signal; and a control circuit that accesses the image signal and the stored signal. An unevenness inspection device according to claim 1, characterized in that: