JPH02190706A - Pattern terminal part inspecting device - Google Patents

Abstract

PURPOSE:To accurately detect a defect part by providing a detection window which has a defect detection window and a projection detection window. CONSTITUTION:A window generating circuit 9 generates the detection window 10 including the defect detection window and projection detection window centering on a gravity center position signal 8. Further, a defect detecting circuit 11 outputs a defect signal 12 by deciding whether or not there is a defect from whether or not there is a point which is in the defect detection window included in the window 10 and not on the pattern of a binary-coded image signal 4. Then a projection extracting circuit 13 extracts only a point which is outside the projection detection window and on the pattern of the signal 4 to output a projection extraction image signal 14. Then a projection detection part 15 regards a part which is narrower than preset a definite width by using the signal 14 to output a projection signal 16. Then a defect decision circuit 17 decides whether or not the terminal end part of the pattern has a defect from the signals 12 and 16 to output a defect signal 18.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention determines whether there is a defect at the end of a pattern to be inspected on a printed wiring board (printed circuit board) scanned and read by a photoelectric scanner. The present invention relates to a pattern end inspection device.

[Conventional technology]

As a conventional technique for determining whether or not there is a defect at the end of a pattern to be inspected on a printed wiring board (printed circuit board), a method using a dedicated inspection mask is well known (for example, Muto et al. Ando: [Automation of visual inspection of printed circuit boards], Mechanical Design, Vol. 29, No. 2, P87-96
．． 1985).

FIG. 6 is a plan view showing an example of a conventional means for detecting defects at the end of a pattern using a dedicated inspection mask. In FIG. 6, when all the points on the inspection mask 33 are not on the pattern and the inspection area 31 includes points on the pattern, it is determined that the pattern to be inspected 32 has a defect.

[Problem to be solved by the invention]

The conventional means for detecting defects at the end of a pattern as described above makes determinations based on an inspection mask, and therefore has the drawback that detection may not be possible depending on the shape of the defect.

[Means to solve the problem]

The pattern end inspection device of the present invention includes a photoelectric conversion scanner that scans and reads out a pattern to be inspected on a printed wiring board;
The input image signal read by the photoelectric conversion scanner is set to "0".
and a binarization circuit that converts and outputs a binary image signal of "1"; An end portion detection circuit detects only the end portion of the pattern to be inspected by scanning in synchronization with raster scan and sends out an end detection image signal; and a center of gravity position of the end portion by inputting the end detection image signal. a center of gravity detection circuit that detects the center of gravity and outputs a center of gravity position signal; a window generation circuit that generates a detection window including a defect detection window and a protrusion/detection window having preset dimensions centered on the center of gravity position signal; a defect detection circuit that outputs a defect signal by determining the presence or absence of a defect based on the presence or absence of a point inside the defect detection window that is included in the detection window and is not on the pattern of the binarized image signal; a protrusion extraction circuit that extracts only points on the pattern of the binarized image signal among points outside the protrusion detection window included in the protrusion detection window and outputs a protrusion extraction image signal;
a protrusion detection circuit that detects a portion having a predetermined width or less as a protrusion from the protrusion extraction image signal and outputs a protrusion signal; and a defect determination circuit that determines the presence or absence of a defect and outputs a defect signal.

〔Example〕

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

FIG. 1 is a block diagram showing one embodiment of the present invention.

In FIG. 1, an input image signal 2 read out by scanning a photoelectric conversion scanner 1 is converted into a binary image signal 4 of "0" and 1°' by a binarization circuit 3 and output. The terminal end detection circuit 5 which inputs this binary image signal 4 has two
The 0 center of gravity detection circuit 7 scans the line removal mask having the dimensions preliminarily set in the digitized image signal 4 in synchronization with the raster scan, detects only the end of the pattern, and sends out the end detection image signal 6. , a terminal end detection image signal 6 is input, the center of gravity position of the terminal end is detected, and a center of gravity position signal 8 is output. The window generating circuit 9 generates a detection window 10 including a defect detection window and a protrusion detection window having predetermined dimensions around the center of gravity position signal 8 . The defect detection circuit 11 determines the presence or absence of a defect based on the presence or absence of a point inside the defect detection window included in the detection window 10 that is not on the pattern of the binarized image signal 4, and outputs a defect signal 12. . The protrusion extraction circuit 13 extracts only points on the pattern of the binary image signal 4 that are included in the detection window 10 and are outside the protrusion detection window, and outputs the protrusion extraction image signal 14. The protrusion detection circuit 15 detects a portion smaller than a predetermined width from the protrusion extraction image signal 14 as a protrusion, and outputs a protrusion signal 16. The defect determination circuit 17 determines whether there is a defect at the end of the pattern based on the defect signal 12 and the protrusion signal 16 and outputs a defect signal 18 .

Next, details of the operation of each part will be explained with reference to FIGS. 2 to 5.

FIG. 2 is an explanatory diagram showing the operating principle of the termination detection circuit of the embodiment shown in FIG. 1.

In FIG. 2, a line removal mask 23 with preset dimensions is scanned over an input image 20 in synchronization with raster scanning, and only the points where all the points inside the line removal mask 23 are on the pattern are removed. Take it out.

FIG. 3 is an image diagram showing an example of a termination detection image detected by the termination detection circuit of the embodiment shown in FIG. The center of gravity detection circuit 7 determines the center of gravity position of the terminal position signal 25 shown in FIG.

FIG. 4 is an explanatory diagram showing the defect detection and protrusion extraction method of the embodiment shown in FIG.

In FIG. 4, by finding points inside the defect detection window 26 that are not on the pattern, a defect 29 can be detected. Further, by finding points on the pattern outside the protrusion detection window 27, a protrusion extraction image can be extracted.

FIG. 5 is a plan view showing an example of the protrusion extraction image extracted as described above.

The protrusion extraction image 30 in FIG.
can be detected.

〔Effect of the invention〕

As explained above, the pattern end portion inspection device of the present invention detects the end portion of a pattern by using a detection window having a defect detection window and a protrusion detection window instead of the conventionally used inspection mask. Since defective portions and protrusions can be detected, there is an effect that defective portions can be detected with high accuracy regardless of the shape of the defect.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing one embodiment of the present invention, FIG. 2 is an explanatory diagram showing the operating principle of the termination detection circuit of the embodiment of FIG. 1, and FIG. 3 is a diagram of the termination of the embodiment of FIG. 1. FIG. 4 is an explanatory diagram showing the defect detection and protrusion extraction method of the embodiment of FIG. 1;
FIG. 5 is a plan view showing an example of a protrusion extraction image, and FIG. 6 is a plan view showing an example of a conventional pattern defect detection means using a dedicated inspection mask. 1...Photoelectric conversion scanner, 2...Input image signal, 3...Binarization circuit, 4...
Binarized image signal, 5... End portion detection circuit, 6.
... End detection image signal, 7 ... Center of gravity detection circuit, 8 ... Center of gravity position signal, 9 ... Window generation circuit, 10 ... Detection window, 11
・・・・・・Deficiency detection circuit, 12・old・defective signal, 1
3... Protrusion extraction circuit, 14... Protrusion extraction image signal, 15... Protrusion detection circuit, 16...
... Protrusion signal, 17 ... Defect determination circuit, 1
8...--Defect signal.

Claims (1)

[Claims] A photoelectric conversion scanner that scans and reads out the pattern to be inspected on a printed wiring board, and a binary image signal that converts the input image signal read by the photoelectric conversion scanner into a binary image signal of "0" and "1" and outputs it. A conversion circuit inputs the binarized image signal and scans a line removal mask having dimensions preset in the binarized image signal in synchronization with raster scanning, thereby removing only the end portion of the pattern to be inspected. a termination detection circuit that detects and sends a termination detection image signal;
a center of gravity detection circuit that inputs the end detection image signal, detects the center of gravity of the end of the image signal, and outputs a center of gravity position signal, and a defect detection window and protrusion detection having dimensions preset around the center of gravity position signal. A window generation circuit generates a detection window including a window, and the presence or absence of a defect is determined based on the presence or absence of a point inside the defect detection window included in the detection window that is not on the pattern of the binarized image signal. a defect detection circuit that outputs a defect signal based on the detection window; and a defect detection circuit that extracts only points that are included in the detection window and are on the pattern of the binarized image signal outside the protrusion detection window and outputs a protrusion extraction image signal. a protrusion extraction circuit; a protrusion detection circuit that detects a portion smaller than a predetermined width from the protrusion extraction image signal as a protrusion and outputs a protrusion signal; A pattern end portion inspection device comprising: a defect determination circuit that determines the presence or absence of a defect at the end portion of a pattern and outputs a defect signal.