JPH01273183A - Position discriminating method - Google Patents

Abstract

PURPOSE:To exactly discriminate the position of a reference mark even in case a resist, a flux or solder, etc., are placed on the reference mark by placing an illumination light source on the side opposite to a video camera with regard to a printed board, and photographing a transmission light beam by the video camera. CONSTITUTION:A supporting base 2 consists of a light transmissive material such as glass or an acryl resin is irradiated with illuminating light from an illumination light source 4 which has been installed on the opposite side to a video camera 3 through a printed circuit board 1 which has been placed on this supporting base 2, and a light beam which has transmitted through the supporting base 2 and the printed circuit board 1 is photographed by the video camera 3 and brought to image processing. Accordingly, even if solder 7 or a flux 8 is placed on a reference mark 6 (6') which has been formed on the printed circuit board 1, an illuminating light beam which arrives from its reverse side is made incident on the video camera as a silhouette for showing an original specific shape without being subjected to a pattern deformation caused by an influence of the solder 7 or the flux 8. In such a way, the pattern which has been brought to image processing is obtained as a correct pattern.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a position identification method for accurately positioning other members on the surface of a plate-shaped body, and in particular to mounting electronic components on a printed circuit board, The present invention relates to a position identification method for accurately identifying the position between a plate-shaped body and another member or between plate-shaped bodies, such as stacking original print sheets on a substrate material.

[Conventional technology]

With the spread of image processing technology, position identification using an image processing system using a video camera has come to be used in many fields.

In particular, the video camera is used for mounting electronic components such as flat pack ICs on printed circuit boards that require high mutual positioning accuracy, for stacking original print sheets in the printed circuit board manufacturing process, and for other highly accurate positioning tasks. The image processing system used is used.

A conventional position identification method using image processing using this type of video camera is applied to a flat pack IC on a printed circuit board.
The mounting will be explained using FIGS. 5 to 8 as an example.

FIG. 5 is an explanatory diagram of a prior art position identification method, 1
is a printed circuit board, 2 is a support stand, 3 is a video camera,
5 is a flat pack IC, and 6, 6° is a reference mark. In the figure, the printed circuit board 1 and the flat pack IC are shown in a simplified manner to simplify the explanation.

In the figure, a reference mark 6.6' having a specific shape is attached to a part of the printed circuit board 1 as a reference for setting the mounting position of the flat pack IC 5. It is desirable that the reference mark 6.6'' has a simple shape that can be easily distinguished from other circuit patterns in image processing, and is not limited to the illustrated shape.

Furthermore, since the material of the printed circuit board 1 is based on plastics such as epoxy resin and polyimide resin, the translucent 0 circuit pattern and reference mark are formed by etching conductors such as laminated copper foil. However, the reference mark may be marked by an appropriate method after the circuit pattern is formed.

In such a configuration, when positioning and mounting the flat pack IC 5 at a predetermined position on the printed circuit board 1 placed on the support stand 2, the above predetermined position is specified and the flat pack IC 5 is mounted at the correct position. In order to determine the position, a reference mark 6.6° having a specific shape is attached to at least a part of the printed circuit board 1, and this reference mark 6
(6°) is drawn with the video camera 3, the video signal obtained by the drawing is image-processed to recognize the specific shape, and the specific position is identified using that position as a reference position. There is.

The printed circuit board 1 is illuminated from the same side as the video camera 3, and the video camera 3 photographs the illumination light reflected from the printed circuit board 1.

Figure 6 shows an example of the reference mark (a) and a pattern (b) obtained in image processing 1. The reference mark in (a) is converted into a video signal by scanning a mask with a video camera, etc. For example, by applying contrast enhancement or AD conversion at a binary level, a pattern (b) of a specific shape is obtained, and by comparing this with a separately prepared mask pattern, the position of the reference mark on the printed circuit board is recognized. Then, based on this reference mark position, a specific position for mounting the flat pack IC is identified.

After identifying the specific position, the flat pack IC mounting jig (not shown) or the support base 2 is moved in the X-Y direction to mount the flat pack IC at a predetermined position.

(Problem to be Solved by the Invention) However, in the above-mentioned conventional technology, since the photographing light of the video camera is a reflected beam of illumination light, if there is resist on the fiducial mark, the illumination conditions are not very good. In addition to the problems that the pattern image is unstable and it takes time to adjust the lighting, the following problems occur.

FIG. 7 is an explanatory diagram when flux is applied on the reference mark, (al is a partial cross-sectional view of the printed circuit board 1 provided with the reference mark 6 (6°),
indicates the flux, and (bl indicates the recognition pattern of the reference mark shown in (a)).

As shown in the figure, when the flux 8 is placed on the printed circuit board 1 covering the reference mark 6 (6'),
This flux causes the illumination light to be diffusely reflected.
As shown in l! ! It becomes a double-identified image, and correct position identification becomes impossible.

FIG. 8 is an explanatory diagram when solder is placed on the reference mark, and (a) is a partial cross-sectional view of the printed circuit board 1 in which the solder 7 is placed on the reference mark 6 (6'). , (b
l indicates the recognition pattern of the reference mark shown in (8).

As shown in the figure, when the solder 7 is placed on the reference mark 6 (6°), the illumination light is diffusely reflected by the solder, resulting in a recognized image as shown in figure (b). It also becomes impossible to identify the correct location.

An object of the present invention is to solve the above-mentioned problems of the prior art, and to accurately recognize the pattern of the fiducial mark and correctly identify its position even when resist, flux, solder, etc. are on the fiducial mark. The object of the present invention is to provide a location identification method that allows the user to perform the following tasks.

[Means to solve the problem]

To achieve the above object, the present invention provides a method for arranging an illumination light source of a printed circuit board on the side opposite to a video camera with respect to the printed circuit board, and photographing the Tingze light beam of at least the fiducial mark portion with the video camera. It is distinctive in that it was adopted.

[Effect]

Since the printed circuit board is translucent, the transmitted light allows the original pattern to enter the video camera as a silhouette even if resist flux or solder is on the fiducial mark, resulting in a stable image.

〔Example〕

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

FIG. 1 is an explanatory diagram of one embodiment of the present invention, in which 1 is a printed circuit board, 2 is a support stand, 3 is a video camera, 4 is an illumination light source, 5 is a flat pack IC as a component, 6, 6
' is a fiducial mark.

In the figure, a circuit pattern is formed on a printed circuit board 1, and a specific position for mounting, for example, a flat pack IC 5 is set in the circuit pattern. The figure shows that the flat pack IC 5 is mounted on the printed circuit board 1 at the above-mentioned specific position. This flat pack IC 5 has a large number of connection pins, and predetermined circuit patterns are formed at specific positions on the printed circuit board 1 corresponding to these connection pins. Therefore, when mounting such an electronic component with an automatic mounting machine, the predetermined circuit pattern and the connection pins need to be correctly positioned. Therefore, reference marks 6 (6') are provided at specific locations on the printed circuit board 1 to serve as positional references.

This reference mark is usually formed at the same time as the circuit pattern forming process, but is not limited to this, and may be formed separately by an appropriate means.

The support base 2 is made of glass, acrylic resin, or other translucent material, and the video camera 3 receives light from an illumination light source 4 installed on the opposite side of the support base 2 via the printed circuit board 1 placed on the support base 2. The light rays irradiated by the illumination light and transmitted through the support base 2 and the printed circuit board 1 are photographed by the video camera 3 and subjected to image processing by an image processing device (not shown).

FIG. 2 is an explanatory view of the main part of FIG. 1, and the light beam from the illumination light B4 passes through the support base 2 and the printed circuit board 1 and reaches the video camera. At this time, the pattern of the reference mark 6 (6°) provided on the printed circuit board 1 is photographed as a silhouette by a video camera, and as explained in FIG. 6, this is image-processed to obtain the pattern. It is.

FIG. 3 is an explanatory diagram of main parts of another embodiment of the present invention, in which the support base 20 is not limited to a transparent material, but instead supports the printed circuit board l and at least , hole 2 in the part corresponding to the part containing fiducial mark 6 (6”)
1 is formed. In this configuration, the light beam from the illumination light source 4 directly passes through the printed circuit board 1, and the silhouette of the reference mark 6 (6') formed thereon is photographed with a video camera, and the image is processed in the same manner as described above. The reference position is identified based on the pattern.

FIG. 4 is an explanatory diagram of main parts for detailed explanation of the present invention,
As shown in (a), solder 7 or flux 8 is applied to the reference mark 6 (6') formed on the printed circuit board 1.
Even if the video camera is placed on the video camera, the illumination light beam coming from the back surface is not subjected to pattern deformation due to the influence of the solder 7 or the flux 8, and enters the video camera as a silhouette showing the original specific shape. The image-processed pattern is Tb in the same figure.
) is obtained as a correct pattern. Furthermore, even if the printed circuit board l is coated with a masking material 9 for solder dipping, a stable reference mark pattern can be obtained by simply increasing the illumination light.

FIG. 9 is a comparison diagram of the position identification method of the present invention and the conventional position identification method. As is clear from the figure, according to the present invention, a good reference position can be achieved in any state of the reference mark. can be identified.

Note that, as described above, the present invention is not limited to mounting electronic components on a printed circuit board, but can also be applied to identifying the positions of members on two boards.

〔Effect of the invention〕

As explained above, according to the present invention, there is a large difference between the silhouette of the position where the fiducial mark is applied and the brightness of its surroundings, so the positional accuracy of the fiducial mark is not affected by flux, resist, solder, or masking material. In addition, the correct position can be identified without being affected by changes in surrounding brightness.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of one embodiment of the present invention, FIG. 2 is an explanatory diagram of the main part of FIG. 1, FIG. 3 is an explanatory diagram of the main part of another embodiment of the invention, and FIG. 4 is an explanatory diagram of the main part of FIG. FIG. 5 is an explanatory diagram of the prior art, FIG. 6 is a diagram showing an example of the reference mark and its image processing pattern, and FIG. 7 is a diagram showing the reference mark with flux applied to it. FIG. 8 is an explanatory diagram when solder is on the reference mark, and FIG. 9 is a comparison diagram between the present invention and the prior art. 1...--Printed circuit board, 2...--Support stand, 3--...Video camera, 4--...
Illumination light source, 5・---・Electronic components, 6,6゛−・−・
-Reference mark. Agent: Patent Attorney Kenjibu 2 (1 other person) 1... Bunono) IEI Su 1 [late 2, branch: Yoriai 3]
・C゛Teokamefu 4°° January Moonlight;,! 5.
;-shija &6.6'・4*7-ri Figure 2 Figure 3 (Q) (b) 5th Ward Figure 6 ((1) (b) Figure 7 (a) (b) Figure 8 (Q) (b)

Claims (3)

[Claims] (1) In a position identification method for identifying a specific position on the surface of a translucent plate-like body by image processing using a video camera, the translucent plate-like body includes a part of the translucent plate-like body that has an identification function for recognizing the specific position. an illumination light source is disposed on the opposite side of the translucent plate-like body from the video camera, and a light beam from the illumination light source illuminates the translucent plate-like body including the fiducial mark; Position identification characterized in that the shape of the reference mark formed by irradiating the reference mark is imaged by a video camera, the position of the reference mark is recognized by performing image processing, and the specific position is identified. Method. (2) The position identification method according to claim (1), wherein the light-transmitting plate-like body is placed on a support made of a transparent material, and the illumination light source is arranged via the support. (3) The light-transmitting plate-like body is placed on a support base, and the support base has a hole through which the light beam from the illumination light source passes through at least the reference mark position and reaches the video camera. The position identification method according to claim 1, characterized in that: