JPS62282249A - Pattern detector - Google Patents

Abstract

PURPOSE:To take out only a true pattern while removing the erroneously detected pattern generated in an invisible region, by leaving the common part of image binary information obtained by a detection from two directions different from each other while removing the other parts thereof. CONSTITUTION:In order to obtain binary image signals in X- and Y-axis directions, the X-direction signal being the output of a line sensor is applied to a CCD signal processing circuit 16x to perform black line detection processing and the image data binarized by a binarization circuit 17x is stored in a buffer memory 18. The stored binarized image signal data is inputted to one of the input terminals of an AND gate circuit 19. Further, a substrate mount stand is rotated by 90 deg. and the Y-direction signal obtained by Y-direction scanning is applied to a CCD signal processing circuit 16y to perform black line detection processing and the image data binarized by a binarization circuit 17y is applied to the other input terminal of the circuit 19. Because no AND condition is formed in the invisible region in the circuit 19, an erroneously detected pattern is removed and only a true pattern is taken out.

Description

[Detailed Description of the Invention] 3. Detailed Description of the Invention [Summary] The present invention provides a pattern detection device in which illumination is applied to detect a pattern formed on a test object, particularly a printed circuit board, using a black line mask. When detecting the black line on the pattern by reflection, the object to be detected is detected from the Y-axis and the Y-axis direction, and the pattern is thicker than the actual size due to the invisible part of the pattern. The present invention provides a pattern detection device which detects a true pattern by an output obtained by ANDing detected output patterns detected in two axial directions: the Y-axis and the Y-axis.

[Industrial application field]

The present invention relates to a pattern detection device for detecting a pattern on an object to be inspected, such as a printed circuit board, and in particular detects a pattern from two directions: a first direction and a second direction perpendicular to the first direction. The present invention relates to a pattern detection device that prevents erroneous detection of a pattern by ANDing the respective detection outputs.

In recent years, printed circuit board patterns have become more multilayered and denser, and there is a demand for the development of pattern inspection equipment that can handle the increasingly complex and dense patterns of printed circuit boards.

[Traditional techniques]

As a conventional pattern detection device, there is a detection device that detects a black line projected onto a pattern by an illumination method using a black line mask as shown in FIG. It is being

That is, in FIG. 4, reference numeral 1 indicates a printed circuit board of the object to be inspected, and a pattern 2 made of copper foil is formed on the printed circuit board. Reference numeral 3 denotes a light source constituting an illumination means disposed on the pattern 2, and the illumination light from the light source forms a black line 6 on the pattern 2 through a black line mask 4 and a mask imaging lens 5. A striped black pattern 4a is formed on the black line mask 4, and since the light from the illumination means does not pass through the black pattern portion, the black line 6 imaged on the pattern 2 of the printed circuit board l is black ( The other portion becomes a bright portion 7. This blank line 6 is detected from an oblique direction by a detection means such as a line sensor 9 via a reflective imaging lens 8.

According to such a pattern detection device, since the pattern portion does not shine, it is possible to obtain a detection device that is easy to detect.

[Problem that the invention seeks to solve]

According to the conventional configuration described above, there are problems caused by detection or illumination from an oblique direction, as shown in FIG. Occur.

That is, in FIG. 5 (al is a printed circuit board and its pattern enlarged from the side), a black line is projected onto the pattern via a black line mask by illumination light 3a from the light source 3 of the illumination means. When detecting the black line portion on this projected pattern with the line sensor 9, this occurs due to the height of the pattern because the height of the pattern in the Z-axis direction is not negligible compared to the width of the pattern 2. Only the invisible part 10 is larger than the actual pattern.If the actual pattern 2 shown in Figure 5(a) is circular, it will be larger than the original circular pattern as shown by the detection signal 11 in Figure 5 (bl). In the pattern 2, which is a shape, the invisible portion 10 causes a brim shape in a certain direction, resulting in an erroneous detection portion 12 due to the invisible portion.

[Means for Solving the Problems] The present invention was made in view of the above-mentioned drawbacks, and its purpose is to create a pattern that does not cause false detection due to invisible parts even when using a black line mask illumination method. There is a detection device to obtain. Figure 1(a).

fb) and fc) are detection signal patterns for explaining the principle of the pattern detection device of the present invention.
As shown in a), a black line is projected onto a pattern on a printed circuit board through a black line mask, and the pattern is detected from an oblique direction by a detection means. When the pattern 2 of the printed circuit board is a circle, the erroneous detection part due to the invisible part 10 is, for example, a flange-shaped part 10X formed in the X-axis direction. Next, if the same circular pattern is rotated in the Y-axis direction, which is 90 degrees different from the As shown in FIG. 2, for example, a flange-shaped portion 10Y is formed in the Y-axis direction at the erroneously detected portion due to the invisible portion IO.

These binary images I and J (Fig. 1(a), (bl
) is passed through an AND gate circuit and the value of InJ is taken to obtain a composite image. As shown in Figure 1 (C1), the AND condition does not hold for the brim section 10X and IOY, so the original circular pattern 2 is obtained. Only that can be taken out.

[For production]

In the present invention, erroneous detection patterns caused by invisible areas are removed by leaving only common parts of image binary information obtained by performing detection or illumination from two different directions and removing the rest.

〔Example〕

Hereinafter, one embodiment of the present invention will be described in detail with reference to FIGS. 2(al), (b) and 3.

FIGS. 2A and 2B show perspective views of a pattern and a rotating means in which the pattern-formed printed circuit board of the present invention is rotated in 90 degrees different directions for illumination and detection, FIG. 3 is a system diagram of the signal processing system of the pattern detection device of the present invention.

In FIGS. 2(a) and (bl), the printed circuit board 1 is placed on the board mounting table 13 and moved in the direction of the arrow as shown by the arrow, and the illumination light 3a from the light 'R3 which is the illumination means is applied to the pattern surface. 2 and detects the reflected black line portion on the pattern 2 on the line sensor 9 of the detection means arranged obliquely in the X-axis direction.At this time, the binarized image is irradiated in the X-axis direction. There is a turntable (not shown) at the lower end of the substrate mounting table 13, and the shaft 15a fixed at the center of the turntable is located at the center of the fixed substrate 14 provided at the lower end of the turntable. It is coupled to the rotor shaft of a drive means 15 such as a pulse motor by passing through a through hole bored in the 2. In the state shown in FIG. As shown, by energizing the driving means 15, the printed circuit board 1 is rotated by 90 degrees as shown in FIG. is the moving direction indicated by the arrow on the print board 1, and at this time the line sensor 9 is arranged diagonally in the Y-axis direction, so the binarized image of the black line portion illuminated from the vertical direction is in the Y-axis direction. The pattern will be longer than it actually is.

That is, if the pattern 2 is circular, then the pattern shown in FIG. 1(a) or (b)
A binarized image as shown in i is obtained.

In order to obtain binary image signals in the X-axis and Y-axis directions in this way, as shown in FIG. The processed image data binarized by the binarization circuit 17X is stored in the buffer memory 18. Next, the board mounting table on which the printed circuit board 1 is placed is rotated by 90 degrees to perform Y-direction scanning, and the obtained Y-direction signal is applied to the CCD signal processing circuit 16y to perform black line detection processing, and then to the binary conversion circuit 17y. The converted image data is applied to one input terminal of the AND gate circuit 19.

On the other hand, the binarized image signal data obtained by scanning in the X direction and stored in the Banoffer memory is applied to the other input terminal of the AND gate circuit 19. This kind of AND gate output is generated by the erroneous detection unit 1 due to the invisible part shown in Figure 1.
0X, IOY are not output and only true pattern 2 is the first
It can be taken out as shown in Figure (C1). In the above example, the case where the pattern was rotated by 90 degrees was described, but 30'
The rotation may be made as appropriate within a range of about 33 degrees, and in short, it is sufficient as long as the X and Y direction erroneous detection parts do not overlap.

〔Effect of the invention〕

The present invention is configured and operated as described above, so that it is possible to easily remove the influence of invisible areas caused by patterned copper foil, and to obtain a pattern detection device that can detect the true pattern of a printed circuit board. It has the characteristic of being able to

[Brief explanation of the drawing]

Figures 1 (a) to (C1 are schematic diagrams of image patterns for explaining the principle of operation of the pattern detection device of the present invention, and Figures 2 (al and (bl) show the configuration of the pattern detection device of the present invention. 3 is a system diagram showing the signal processing system of the pattern detection device of the present invention, FIG. 4 is a schematic perspective view showing the Bra and Klein illumination in the conventional pattern detection device, and FIG. ) is a schematic side view illustrating the invisible part caused by the side surface and pattern of a conventional printed circuit board, and FIG. 5 (bl is a schematic plan view of a detection signal pattern caused by the influence of the invisible part. 1 print base, 2...pattern, 3...light source, 4...black line mask, 6...blank line, 7...bright area, 9...line sensor, 10... Invisible part, 11... Detection signal, 12... Erroneous detection part due to invisible part, 13... Substrate mounting table, 14... Substrate, 15... Driving means, 16x, t6y...-ccD signal Processing circuit, 17x, 1
7y... Binarization circuit, 18... Buffer memory, 19... AND gate circuit.

Claims (1)

[Scope of Claims] 1) Illumination means (3) that illuminates the pattern of the object to be inspected via a black line mask, and detection means (9) that detects the black line imaged on the pattern of the object to be inspected. )
The detection means detects the black line imaged on the pattern by the illumination means from one direction, and detects the object to be inspected from a direction different from the one direction by a predetermined angle. A pattern detection device comprising: a synthesis means for synthesizing detection signals. 2) The pattern detection device according to claim 1, wherein the table on which the object to be detected is placed is rotated by 90 degrees in order to obtain the two detection signals. 3) Rotate the object to be measured at 90° to obtain the two detection signals.
The pattern detection device according to claim 1, wherein the pattern detection device is rotated. 4) The pattern detection device according to claim 1, wherein a black line mask that illuminates the object to be detected is rotated by 90 degrees in order to obtain the two detection signals. 5) The pattern detection device according to claim 1, wherein the combining means for obtaining the two detection signals is an AND gate circuit.