JPH0672763B2 - Mounted component inspection device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Outline] The present invention inspects a mounting state of a component by irradiating a printed board on which a component is mounted with a slit-shaped light beam and detecting the reflected light with a line sensor. In the mounted component inspection apparatus, the two line sensors detect the respective reflected lights from the board portion of the printed board and the upper surface of the component due to the irradiation of the slit-shaped light beam, and based on the comparison result of their detection outputs. By determining the mounting state of the component by using the above, the mounting state of the component can be inspected with very high contrast even if the reflectance of the surface to be detected is not uniform.

[Industrial application field]

The present invention relates to a mounted component inspection apparatus that optically and automatically inspects a mounted state (for example, presence / absence, positional deviation, etc.) of electronic components (particularly chip components) mounted on a printed board.

Currently, with the miniaturization of semiconductor elements and other electronic components,
The density of printed boards is increasing. The number of printed boards on which chip components are mounted has increased, and it is desired to automatically inspect this mounting state. For that purpose, it is necessary to detect the parts with good contrast and accurately.

[Conventional technology]

FIG. 5 shows an optical system related to a conventional mounted component inspection apparatus.
In the figure, the substrate section R of the printed board P is formed by using the optical cutting method.
Only the component Q having the predetermined height h above is detected. That is, while mounting the printed board P on the stage 1 and moving it in the direction of arrow A, the semiconductor laser 2,
A slit-shaped light beam (hereinafter referred to as a slit beam) l ₁ created by the pre-lens 3 and the cylindrical lens 4 is irradiated onto the printed board P from obliquely above.
Then, only the reflected light l ₂ from the predetermined height h is imaged by the one line sensor 6 such as CCD through the imaging lens 5. An image obtained when the detection signal intensity of the line sensor 6 is "1" when the slice level is equal to or higher than a predetermined slice level and "0" when the intensity is equal to or lower than the predetermined slice level, that is, an image in which only the component Q having the predetermined height h is distinguished from others Based on this, the mounting state is inspected.

[Problems to be solved by the invention]

In the above conventional apparatus, even if there is a component at the height h of interest, if the color of the surface of this component is black, the reflected light may be weak and may not be detected sufficiently. Even if there is a part outside the height h, if there is a bright part around the part, it may be detected as a predetermined part by the light that goes around from there.

So if you try to detect black parts completely,
As shown in the detection example (i) of FIG. 6, not only the component body Q ₁ (black portion) but also the bright electrode portion P on the printed board P
₁ was also detected higher than the slice level due to the wraparound of light from there, and all were judged to be "1", that is, a component. On the other hand, when the reflected light l ₃ from the height of the board portion R is detected to completely detect a portion other than the component as a shadow, the detection example (i
As shown in i), the electrode part Q which is the bright part on the part Q
₂ was also detected as a part other than the parts due to the wraparound of light from there.

That is, the conventional device has a problem that the contrast (S / N) is poor.

In view of the above problems, it is an object of the present invention to provide a mounted component inspection device capable of detecting a component with good contrast (S / N) even if the reflectance of the surface to be detected is not uniform.

[Means for solving problems]

The present invention detects the reflected light from the board portion of the printed board and the reflected light from the upper surface of the component of a predetermined height by the first and second line sensors, respectively, and compares the intensities of the output signals with each other,
It is characterized in that the mounting state of the component having the predetermined height is determined based on the comparison result.

[Work]

In general, even for a black component, the reflected light detected from the upper surface thereof is stronger than the reflected light detected from the substrate portion. Further, the reflected light directly detected from the bright portion (for example, the electrode portion) on the substrate portion is stronger than the light reflected from the portion and detected as the reflected light from the component. Similarly, the reflected light that is directly detected from the bright portion (for example, the electrode portion) on the component is stronger than the light that is reflected from the portion and that is detected as the reflected light from the substrate.

In this way, regardless of the lightness or darkness of the surface to be detected on the printed board, either one of the intensities of the reflected light increases depending on whether or not there is a portion. When the sensor detects the reflected light from each of the substrate portion and the upper surface of the component, the intensity of the detection signal also increases according to the intensity of the reflected light. Therefore, if the intensities of the detection signals of the two line sensors are compared with each other to see which is greater, it is determined whether the detected object is a component or a board portion by the influence of the light wraparound as described above. You can make an accurate judgment without receiving it. That is, it is possible to detect a component with very high contrast without detecting the electrode portion of the component by mistake with the substrate portion or by detecting the electrode portion on the substrate portion by mistake with the component.

〔Example〕

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a configuration diagram showing a light irradiation means and a light detection means according to an embodiment of the present invention.

First, the light irradiation means is a semiconductor laser 12 and a collimator lens.
A printed board P, which is composed of a cylindrical lens 13 and a cylindrical lens 14, is placed on the stage 11 and moves in the direction of arrow A.
On the other hand, the slit beam l ₁ is emitted obliquely from above. The slit beam l ₁ is obtained by converting the laser light output from the semiconductor laser 12 into parallel light by the collimator lens 13 and further forming the slit light by the cylindrical lens 14. The direction of the light cutting line formed on the printed board P by the slit beam ₁₁ is set to be orthogonal to the moving direction of the printed board P (arrow A).

Next, the light detecting means is composed of an imaging lens 15, a beam splitter 16, and two line sensors (for example, CCD line sensor) 17 and 18, and the reflection from the printed board P by irradiation of the slit beam l ₁ is performed. Light (reflected light l ₂ from the upper surface of the component Q having a predetermined height, reflected light from the substrate R)
l ₃ ) is detected from a direction different from the irradiation direction of the slit beam l ₁ . The beam splitter 16 splits the reflected light obtained through the imaging lens 15 into two directions with a 1: 1 intensity ratio. Then, one line sensor 17 is arranged at a position where the reflected light l ₃ from the substrate portion R is imaged among the one of the divided reflected lights, and the above-mentioned component of the other divided reflected light is arranged. The other line sensor 18 is arranged at the position where the reflected light l ₂ from Q is imaged.
That is, the line sensor 17 receives the reflected light l ₃ from the substrate R.
The line sensor 18 detects the reflected light l ₂ from the component Q.

In addition, in order to be able to detect reflected light from various parts having different heights within a certain predetermined range, the line sensor 18 is
It is desirable to use a light receiving surface of each of the light receiving elements that composes the light receiving surface having a rectangular shape elongated corresponding to the height direction of the component. As the other line sensor 17, it is desirable to use one having the above-mentioned shape of a substantially square.

An example of detection of reflected light at each position on the printed board P by the above optical system will be described with reference to FIG.

First, as shown in FIG. 6A, when the slit beam l ₁ is irradiated on the component Q, even if the surface is black,
The reflected light l ₂ from there is stronger than the reflected light l ₃ from the substrate portion R. Therefore, the intensity of the output signal of the line sensor 18 is higher than the output signal of the line sensor 17. Further, the line sensor 18 detects the reflected light l ₂ from the bright portion (for example, the electrode portion Q ₂ shown in FIG. 6) on the component Q, and
Even if a part of the circulated light is detected by the other line sensor 17, the intensity of the output signal of the line sensor 18 is high because the direct reflected light is stronger.
Greater than 17 output signals.

Further, as shown in FIG. 2 (b), the slit beam l ₁ is
When the electrode P ₁ on the substrate R is radiated from above, even if part of the reflected light from the electrode P ₁ wraps around and is detected by the line sensor 18, Since the direct reflected light l ₃ is stronger, the intensity of the output signal of the line sensor 17 is larger than the intensity of the output signal of the line sensor 18.

Further, as shown in FIG. 2 (c), even if the substrate R is a dark resist or the like, the reflected light l ₃ having a certain intensity can be obtained, so that the intensity of the output signal of the line sensor 17 is equal to that of the line sensor 18.
Is greater than the output signal strength of.

From the above, when the slit beam l ₁ is applied to the upper surface of the component Q, the output signal of the line sensor 18 is higher than that of the line sensor 17 even if the reflectance of the surface is not uniform. Has great strength. On the other hand, slit beam l ₁
When the component Q is not radiated on the component Q but is radiated only on the substrate R, the output signal of the line sensor 17 is higher than the output signal of the line sensor 18 even if the reflectance there is not uniform. Has great strength.

Next, a signal processing circuit according to this embodiment is shown in FIG. In the figure, first, the above-mentioned two line sensors 17, 18
The output signal of is supplied to the + input terminals of the comparators 21 and 22, respectively, and the minimum light reference value is supplied to the-input terminals. This lowest light reference value is a value corresponding to the intensity of the detection output signal when the lowest intensity light that can be reflected from the component Q or the board portion R is detected by the line sensor 17 or 18. The comparators 21 and 22 output the comparison results as "1" and "0", and the result is taken out as an output bit A ("1" or "0") via the OR circuit 24. Then, when the reflected light from the normal component Q or the board portion R is detected by at least one of the line sensors 17 and 18, the output bit A becomes "1", and from which of the line sensors 17 and 18, When the light above the minimum light reference value is not detected (for example,
When there is a hole in the board R or an object higher than the component Q exists), the output bit A is "0".
Becomes

Further, in FIG. 3, the output signals of the two line sensors 17 and 18 are respectively fed to the-input terminal of the other comparator 23, +
Input to the input terminal. This comparison result is "1", "0"
And output as output bit B. Then,
When the output signal strength of the line sensor 18 is larger than the output signal strength of the line sensor 17, that is, when the component Q is detected, the output bit B becomes "1". On the other hand, when the output signal intensity of the line sensor 17 is larger than the output signal intensity of the line sensor 18, that is, when only the substrate portion R is detected, the output bit B becomes "0".

Therefore, by checking whether the output bit A is "1" or "0", it is possible to know whether the component Q or the board portion R is detected, and if it is detected (the output bit A is " When the output bit B is "1" or "0", it is possible to know whether the detected one is the component Q or the board portion R by further checking whether the output bit B is "1" or "0".

For example, as shown in FIG.
Q _10, Q ₂₀ is mounted, and if they can hole H in a part, the output signal strength of the line sensors 17 and 18, corresponding to the respective positions, as shown in FIG. (B) Become. Then, from the relationship between the output signal strength and the minimum light reference value, the output bit A becomes as shown in FIG. That is, only the portion of the hole H becomes "0" and the other portions become "1". Next, the output bit B becomes as shown in FIG. 6D from the magnitude relationship between the two output signal intensities. That is, the parts Q ₁₀ and Q ₂₀ are “1”, and the part of the board portion R is “0”. If, as shown in FIG. 6, there are electrode portions Q ₂ and P ₁ on the component Q and the substrate portion R, and light wraps around the electrode portions Q ₂ and P ₁ , detection examples are detected in the respective line sensors 17 and 18. As shown in (i) and (ii), the influence of light wraparound occurs, but the influence of light wraparound does not occur at all in the output bit B obtained by comparing them, and the position of each component is accurately determined. The corresponding value "1" is obtained. In other words, it is possible to detect parts with very good contrast (S / N).

Therefore, by sequentially looking at the output bits A and B, the mounting state such as the presence or absence of a component or the positional deviation can be determined very accurately regardless of whether the detected surface is bright or dark. Further, the output bit B indicates that the comparison result of the detection signals is "1" and "0", which is 2
Since the value is expressed as a value, there is also an advantage that shading (a phenomenon in which the peripheral portion of the image is dark) often seen in an image obtained by directly capturing an image with, for example, a TV camera is eliminated.

〔The invention's effect〕

According to the mounted component inspection apparatus of the present invention, even if the reflectance of the surface to be detected is not uniform, erroneous detection due to light wraparound, etc. can be prevented and component detection with extremely good contrast (S / N) can be performed. Therefore, the mounting state of the component can be inspected very accurately.

[Brief description of drawings]

FIG. 1 is a block diagram showing a light irradiation means and a light detection means according to an embodiment of the present invention, and FIGS. 2 (a) to (c) show an example of reflected light intensity at each position on a printed board P. FIG. 3, FIG. 3 is a circuit diagram showing a signal processing circuit according to the same embodiment, FIGS. 4 (a) to (d) are diagrams for explaining an example of signal processing in the same embodiment, and FIG. FIG. 6 is a configuration diagram showing an optical system related to the above device, and FIG. 6 is a diagram showing an example of the detection signal intensity for explaining the conventional problems. 12 …… semiconductor laser, 13 …… collimating lens, 14 …… cylindrical lens, 15 …… imaging lens, 16 …… beam splitter, 17,18 …… line sensor, 21,22,23 …… comparator, l ₁ …… slit beam, l ₂ , l ₃ …… reflected light.

Claims (10)

[Claims] 1. A light irradiating means (12, 13, 14) for irradiating a slit-shaped light beam (l ₁ ) on a printed board on which components are mounted.
And the reflected light (l ₃ ) from the substrate portion of the printed board and the reflected light (l ₂ ) from the upper surface of the component having a predetermined height, which are caused by the irradiation of the light beam by the light irradiation means, respectively. The light detecting means (15, 16, 17, 18) for detecting from the direction different from the irradiation direction of the light beam by the second line sensor (17, 18)
And a signal processing means (21, 22, 23, 21) for comparing the intensities of the output signals of the first and second line sensors with each other and judging the mounting state of the component having the predetermined height based on the comparison result. twenty four)
A mounting component inspection device comprising: 2. The light irradiating means comprises a semiconductor laser (12) for outputting laser light, a collimator lens (13) for converting the laser light output by the semiconductor laser into parallel light, and the collimator lens. The mounted component inspection device according to claim 1, comprising a cylindrical lens (14) for converting the parallel light thus generated into the slit-shaped light beam. 3. The light detecting means forms an image of each of the reflected lights at different positions via an image forming lens (15) and a beam splitter (16), and the first image is formed on each image forming surface.
The mounted component inspection device according to claim 1 or 2, wherein the first and second line sensors (17, 18) are arranged. 4. The light receiving surface of each light receiving element forming the first line sensor has a substantially square shape, and the light receiving surface has a substantially square shape. Mounted component inspection device. 5. The light receiving surface of each light receiving element forming the second line sensor has a rectangular shape which is long in correspondence with the height direction of the component.
Item 5. The mounted component inspection device according to any one of items 4 to 4. 6. The signal processing means determines whether the intensity of the output signal of the first line sensor is higher or lower than the intensity of the output signal of the second line sensor, and whether the signal is a board portion or a component, respectively. The mounted component inspection device according to any one of claims 1 to 5, wherein: 7. The signal processing means, in addition to performing the comparison, further compares the output signals of the first and second line sensors with a predetermined reference value, and based on the results of these two comparisons, the parts. The mounted component inspection device according to any one of claims 1 to 6, wherein the mounted state is determined. 8. The heights of the board portion and the component are both outside a predetermined measurement range when the output signal intensities of the first and second line sensors are smaller than the predetermined reference value. The mounted component inspection device according to claim 7, wherein the mounted component inspection device is characterized by: 9. The first and second line sensors are both CCs.
The mounted component inspection device according to any one of claims 1 to 8, which is a D line sensor. 10. The mounted component inspection apparatus according to claim 1, wherein the component is a chip component.