JPH0726810B2 - Chip component misalignment inspection device - Google Patents

Description

The present invention relates to an electronic component mounting board inspection device, and more particularly to a detection optical system suitable for automatic displacement inspection after mounting a small size / faceted chip component on a printed circuit board. The present invention relates to a chip component positional deviation inspection device.

[Conventional technology]

A conventional chip component position shift inspection apparatus for a printed circuit board on which chip components are mounted irradiates a target component using a plurality of illuminations as described in JP-A-61-294302, and image input with good contrast and An image is input by emphasizing only a specific object, and the input image is binarized to inspect the positional deviation of components.

Further, as described in Japanese Patent Laid-Open No. 58-135941, a method of determining the outer shape and position of a chip component by irradiating a target with parallel illumination to form a shadow of the target component on a substrate and inputting the shadow as an image. Was taking.

[Problems to be solved by the invention]

In the above-mentioned conventional technique, the method disclosed in Japanese Patent Laid-Open No. 61-294302 does not consider the case where it is difficult to obtain the contrast due to the combination of the target component color and the substrate color, and there is a limit to the target applicable to the inspection.

Further, in the device disclosed in Japanese Patent Laid-Open No. 58-135941, consideration is not given to parts having a more complicated shape such as cylindrical parts and other odd-shaped parts, and there is a limit to the objects to which the inspection can be applied similarly to the above. .

Further, both of the above-mentioned prior arts perform positive light projection, but due to this, due to the high-brightness reflected light from the solder surface, etc., regarding blooming and smear on the image pickup element that occur especially when a solid-state image pickup element is used. No consideration was given, and there was a problem that inspection after soldering would be difficult.

An object of the present invention is to provide a chip component misalignment inspection apparatus that can always perform a stable misalignment inspection of a chip component after soldering to a printed circuit board without being affected by the color / shape of the chip component and the color of the printed circuit board. is there.

[Means for solving problems]

The purpose is to reflect the slit light from the slit light projector by a galvanometer mirror and then project it obliquely to the substrate to project the light cutting line on the board and the mounted chip component, and the light cutting line is printed on the board. A chip component misalignment inspection that detects the misalignment of chip parts by taking an image of the optical cutting line from above from the TV camera so that it is horizontal in the image and analyzing the shape of the light cutting line in the image with the image processing control device. Achieved by the device.

[Action]

In the above-described chip component position shift inspection device, the position of the light cutting line in the image changes depending on the height of the irradiated surface by irradiating the substrate with the slit light obliquely and imaging it from directly above. Therefore, the height of the target can be known by analyzing the shape of the optical cutting line, so that the position of the chip component mounted on the board can be detected from the unevenness of the board surface, and the color / shape of the chip and the board Not affected by color. By laterally irradiating the target with this dicing light cutting line, it is possible to detect the lateral deviation and the vertical deviation of the target chip. In addition, the galvanometer mirror reflects the slit light projected from the slit light projector to irradiate the target with a light cutting line at an arbitrary angle, so that the light can be reliably cut on the chip upper surface for various chip heights. Can irradiate a line. In addition, when the slit light or general irradiation etc. directly hits the metal surface of solder etc. and returns the reflected light of high brightness by imaging the light cutting line irradiated on the object so that it is horizontal in the image. In particular, since it is possible to distinguish a bright vertical line called smear or blooming that occurs when a solid-state image sensor is used from a light cutting line as the direction of the bright line in the image, it is possible to prevent erroneous detection at the time of detecting the light cutting line. .

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 1 to 10.

FIG. 1 is a schematic configuration diagram showing an embodiment of a chip component position shift inspection apparatus according to the present invention. In FIG. 1, 1 is a television camera for imaging an inspection object, 2 is a half mirror, and the two television cameras 1 are optically coupled to each other, and the two television cameras 1 are angularly displaced from each other by 90 ° at the same place. So that it can be imaged. Reference numeral 3 is a slit light projector (slit light projector), and 4 is a mirror for reflecting the slit light projected from the slit light projector 3 to control the irradiation position of the light cutting line on the substrate, for example, a galvano mirror. Reference numeral 5 denotes an XY stage that holds a printed circuit board on which chip components to be inspected are mounted, and an XY stage that can be moved in a plane.
Driven by the table. 6 is a slit light projector 3
Control circuit for controlling the lighting of the display and the operation of the galvano mirror 4 and the XY stage (XY table) 5, 7 is an image processing circuit for processing image data input from the television camera 1, 8 is a control circuit 6 and an image processing circuit. 7 is an image processing control device.

The apparatus shown in FIG. 1 includes a television camera 1, a slit light projector 3, an XY stage (XY table) 5 on which a printed circuit board having a chip component to be inspected is mounted, and image data input from the television camera 1. An electronic component mounting board inspection apparatus including an image processing control apparatus 8 for controlling processing and a system is provided with two slit light projectors 3 so that light cutting lines irradiated on the board are orthogonal to each other, and further projected. Galvano mirror (mirror) controlled by the image processing controller 8 to reflect the slit light and control the irradiation position of each slit light.
4 is provided and two TV camera 1 and a half mirror 2 are provided so that the two light cutting lines irradiated on the substrate can be imaged in the horizontal direction in the image. Is a chip component position shift inspection device configured to detect the position shift of the chip component by analyzing the shape of the light section line by the image processing control device 8.

FIG. 2 is a partial explanatory view of the detection optical system of FIG. First
In the optical system shown in the figure, one TV camera 1, slit light projector 3 and galvano mirror 4 make up one set, and only two sets are prepared. In FIG. 2, one set is seen from the side. The figure is shown. In FIG. 2, the same reference numerals denote the same or corresponding parts throughout the drawings, 9 is a chip part to be inspected, and 10 is a chip part 9.
It is mounted on the XY stage 5 (Fig. 1) with a printed circuit board on which is mounted. Reference numeral 11 denotes a slit light projector 3 which is a chip component 9 to be inspected for an optical cutting line through a galvanometer mirror 4.
It is an input image at the time of capturing and inputting the image when it is irradiated on the camera with the television camera 1.

The television camera 1 shown in FIG. 2 is installed in a direction perpendicular to the substrate 10, and the light cutting line from the slit light projector 3 is reflected by the galvanometer mirror 4 and is obliquely irradiated to the substrate 10. As a result, the light cutting line irradiated on the chip component 9 at a position higher than the surface of the substrate 10 moves above the light cutting line irradiated on the substrate surface on the image 11. In this way, the position of the light cutting line on the image 11 changes depending on the unevenness of the target chip component 9, so that the position of the target chip component 9 can be detected from the shape of the light cutting line on the image 11. In the figure, the positional deviation of the chip component 9 in the X direction can be detected.
Since the height of the chip component 9 to be inspected differs depending on the product type, the slit light projector 4 is configured by the galvano mirror 4 so that the upper surface of the chip component 9 is irradiated with the light cutting line according to the target chip component 9. The slit light from 3 is reflected to control the irradiation position. The control method by the control circuit 6 (FIG. 1) of the galvanometer mirror 4 is performed by controlling the angle of the galvanometer mirror 4 using the data indicating the height of the chip component 9. The image in Figure 2
In order to detect the displacement of the chip part 9 in the Y direction shown by 11, only one set of the optical system shown in FIG. 2 is prepared. Therefore, two TV cameras 1, a slit light projector 3 and a galvano mirror 4 are provided as shown in FIG. 1, and the slit light projector 3 and the galvano mirror 3 are arranged so as to be orthogonal to each other as shown in FIG. .

FIG. 3 is an explanatory diagram of the image pickup method of FIG. As shown in FIG. 3, the television camera 1 shown in FIG. 1 divides a light beam incident from a chip component 9 on a substrate 10 to be inspected into two by a half mirror 2 and displays this image on two television cameras 1.
Image with a and 1b. At this time, the two TV cameras 1a, 1b capture the same target in the image, but the image 11 input from the two TV cameras 1a, 1b is the input image 11a, 11b.
Are orthogonal to each other. This gives the image in Figure 3.
It is possible to detect the positional deviation of the chip component 9 to be inspected in each of the X and Y directions from the shape of the light cutting line on the image as shown in 11a and 11b.

4 and 5 are the input images of FIG. 2 and FIG.
It is explanatory drawing of 11 examples. 12 in FIGS. 4 and 5
Is a high-intensity point, 13 is a high-intensity vertical line, 14 is a high-intensity vertical line due to a light cutting line, and 15 is a high-intensity vertical line due to reflected light. The light cutting lines in FIGS. 2 and 3 above are the input images 11 in FIG.
And, as shown in images 11a and 11b in FIG. 3, the television camera 1 is set so as to be in the horizontal direction in the image and the image is taken. In this way, as shown in image 11 of FIG. 4, when the optical cutting line irradiated on the substrate 10 on which the target chip component 9 is soldered is reflected by the solder or the metallic glossy surface on the substrate 10, This is picked up as a high-brightness point 12 in the image 11 of the television camera 1, and thereby a high-brightness vertical line 13 is generated, which can be easily discriminated as a direction. On the other hand, if the image is taken so that the light cutting line is in the vertical direction in the image as shown in image 11 of FIG. 5, the high brightness vertical line 14 due to the light cutting line and the high brightness generated by the reflected light Point
It is not preferable because it becomes difficult to distinguish the high-intensity vertical line 15 from the 12th line. Next, a circuit configuration and an extraction method for stably extracting the light cutting line from the image when the TV camera 1 captures the light cutting line in the horizontal direction in the image will be described.

FIG. 6 is a schematic configuration diagram of the image processing circuit 7 including the optical cutting line extraction circuit of FIG. In FIG. 6, 16 is an A / D converter, 17 is an image memory, 18 is an optical cutting line extraction circuit, 19 is a position storage memory, 20 is a CPU, 21 is a memory, and 22 is a bus. The image signal input from the television camera 1 shown in FIG. 6 is analog-digital converted by the A / D converter 16 of the image processing circuit 7, and the image memory 17 or the optical cutting line extraction circuit 18 is provided.
Can be entered in. The optical cutting line extraction circuit 18 is an A / D converter 16
Input the image data from and perform the optical cutting line extraction calculation,
The calculation result is output to the position storage memory 19. The control circuit 6 is controlled by the CPU 20, and the slit light projector 3
It controls the galvanometer mirror 4 and the XY stage (XY table) 5.

FIG. 7 is an explanatory view of the optical cutting line extraction method of FIG. In FIG. 7, 11A is an image irradiated with a light cutting line, 11B is an image not irradiated with a light cutting line, and 11C is a difference image. The light cutting line extraction circuit 18 in FIG. 6 uses the image data from the A / D converter 16 to use two images, an image 11A irradiated with the light cutting line and an image 11B not irradiated with the light cutting line, in FIG. Subtraction is performed between these two images 11A and 11B. As a result, the portion that changes between the two images 11A and 11B is only the irradiation portion of the light cutting line, so only the light cutting line is separated from the background and the difference image 11
Extracted as C, the influence of reflected light from the wiring pattern etc. can be removed. The coordinates I and J are the coordinates corresponding to the horizontal and vertical directions of the image, respectively.

FIG. 8 is an explanatory diagram of the brightness distribution of the difference image 11C in FIG. When the brightness distribution is examined in the direction perpendicular to the scanning line with respect to the difference image 11C in FIG. 7, the brightness value F as shown in FIG.
(J) is canceled out except for the irradiation portion of the light cutting line by the slit light, and shows only a very small brightness level due to the influence of the noise component. Therefore, by setting a constant threshold value TH, it is possible to leave only the portion of the light cutting line due to the slit light. The change in brightness of the light cutting line portion due to the slit light shows a normal distribution-like change as shown in FIG.
The position of the light cutting line on the image 11C due to this slit light is considered to be the center of this brightness distribution, so the center value M (I) at the coordinate I is calculated by the weighted average processing by the following equation. Coordinates I and J are coordinates corresponding to the horizontal and vertical directions of the image, respectively, as shown in FIG.

However, F (J) is the brightness value at the coordinate J, and J ₀ and J ₁ are the coordinate values of the coordinate J when the brightness value F (J) shown in FIG. 8 exceeds the threshold value TH. By performing the calculation according to the equation (1) for each coordinate I, the light cutting line is extracted as the next point sequence.

(I, M (I)) I = 0,1, ..., N (2) where N is the number of horizontal pixels of the image 11C.

FIG. 9 is an explanatory diagram of the brightness distribution of the difference image 11C of FIG. 7 having the high-intensity vertical line 13 due to the reflected light. As shown in FIG. 4 above, when there is a high-intensity vertical line 13 on the image 11 generated when the high-intensity point 12 due to the high-intensity reflected light is picked up during the image pickup by irradiation with the light cutting line, Vertical line 13 as shown in Fig. 9
The level of the brightness value F (J) of the difference image 11C above is the coordinate J.
Since the threshold value TH is exceeded over the entire range of, the part subjected to the calculation by the equation (1) covers a wide range. Therefore, when the value of the range W represented by W = J ₁ −J ₀ (3) exceeds a certain threshold value WTH, the calculation result by the equation (1) is cleared only for the vertical line 13 minutes. As a result, it is possible to eliminate the influence of the high-brightness reflected light on the extraction of the light cutting line of the high-brightness vertical line 13. The circuit configuration and the operation of the optical cutting line extraction circuit 18 which performs the optical cutting line extraction processing by the above algorithm will be described below.

FIG. 10 is a circuit configuration block diagram of the optical cutting line extraction circuit 18 of FIG. In FIG. 10, 23 and 24 are image memories, and 25
Is an address generator, 26 is a clock generator, 27 is a differencer,
28 is an adder, 29 is a comparator 30, a difference device, 31 is a multiplier, 32,3
3 is an adder, 34 and 35 are latches, 36 is a divider, 37 is a latch,
38 is a gate.

The image signal input by the TV camera 1 in FIG.
Image memory 23, 24 digitized by D converter 16
Memorized in. Image 11A illuminated by this dicing line
(FIG. 7) is stored in the image memory 23, and the image 11B not irradiated with one light cutting line is sequentially stored in the image memory 24.
The clock generator 26 sends an address to the image memories 23 and 24 so that the address memories 25 can access the image memories 23 and 24 in the direction perpendicular to the scanning lines. The difference unit 27 generates difference image 11C data from the difference between the image 11A data of the image memory 23 irradiated with the light cutting line and the image 11B data of the image memory not irradiated with the light cutting line, and the difference unit 30 generates the difference image 11C data. Brightness value F of the difference image 11C data shown in FIG.
(J) is compared with the threshold TH, and only the data equal to or larger than the threshold TH is processed by the next multiplier 31 and adder 32. That is, the multiplier 31 calculates the product of the coordinate value J of the address generated by the address generator 25 and the difference image 11C data F (J) through the difference device 30 from the difference device 27, and this product F (J ) * J is accumulated and the calculation of the numerator of Formula (1) is performed. Further, the adder 32 accumulates the difference image 11C data F (J) from the difference unit 27 via the difference unit 30 and executes the calculation of the denominator of the equation (1). Latch 3 for each calculation result
The result of division by the divider 36 is held at 4,35 and is divided by the end instruction generated by the address generator 25 after scanning one vertical line.
(I) is output to the latch 37 and is stored in the position storage memory 19 (1).
The central value M (I) data according to the formula is output and stored. The adder 28 outputs the clock output from the clock generator 26 unless the carry is generated from the differentiator 30.
Cumulative addition is performed as long as the operation is executed at 1,32,33. This accumulated result is always displayed by the comparator 29 in the threshold value WTB of the equation (3).
When the accumulated result becomes larger than the threshold value WTH, the latch 37 holding the operation result M (I) is cleared to output zero data to the position storage memory 19, and at the same time, the address generator 25 is reset. Update to next vertical row address occurrence. By the action of the comparator 29, the high-intensity vertical line 13 (fourth line) on the image 11 generated by the reflected light shown in FIG.
It is possible to clear the image data M (I) of the portion including the figure.

According to the present embodiment, it is possible to detect the positional deviation of the small surface-mounted chip component mounted on the printed circuit board without being restricted by the color and shape of the chip and the color of the printed circuit board, and to project the slit light. It is possible to eliminate the influence of vertical bright lines on the image pickup element caused by high-luminance reflected light from a metal surface such as solder on the substrate due to light.

〔The invention's effect〕

According to the present invention, it is possible to detect the positional deviation of the chip component without being limited by the color / shape of the chip component and the color of the printed circuit board, and it is also possible to remove the influence of the reflected light from the solder or the like. There is an effect that the appearance inspection of the mounted chip after attachment can be performed with high reliability.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing an embodiment of a chip component position shift inspection apparatus according to the present invention, FIG. 2 is a partial explanatory view of the detection optical system of FIG. 1, and FIG. 3 is a diagram of the imaging system of FIG. Explanatory drawing, FIG. 4, FIG. 5 is each input image example drawing of FIG. 2, FIG. 3, and FIG.
The figure is a schematic configuration diagram of the image processing circuit of FIG. 1, FIG. 7, and FIG.
Fig. 9 and Fig. 9 are explanatory views of the method of extracting each optical cutting line in Fig. 6,
FIG. 10 is a block diagram of the optical cutting line extraction circuit of FIG. 1 ... TV camera 2 ... Half mirror 3 ... Slit light projector 4 ... Galvano mirror 5 ... XY stage 6 ... Control circuit 7 ... Image processing circuit 8 ... Control device

 ─────────────────────────────────────────────────── ─── Continuation of front page (56) Reference JP-A-58-142208 (JP, A) JP-A-62-39341 (JP, A) JP-A-61-290311 (JP, A)

Claims (3)

[Claims] 1. A slit light irradiating means for irradiating a substrate on which a component is mounted with a first slit light and a second slit light intersecting with the first slit light according to design data of the component. A first imaging unit that horizontally captures an image of reflected light from the surface of the substrate by the first slit light and an image of reflected light from the surface of the sample by the second slit light. An image pickup unit having a second image pickup unit for horizontally picking up the image, and the design data of the position of the component mounted on the board based on the image signal of the reflected light from the component surface imaged by the image pickup unit. An image processing control means for detecting a deviation amount, and a component position deviation inspection device. 2. The component positional deviation inspection device according to claim 1, wherein the first slit light and the second slit light intersect each other at a right angle. 3. The component positional deviation inspection device according to claim 1, wherein the slit light is emitted by controlling an irradiation angle of the component according to a height of the component. .