JPH01121152A - Position recognizing method for printed board - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a method for recognizing the position of a printed circuit board.

[Prior art and its dark problems] Conventionally, when mounting components that require a high degree of mounting accuracy, such as flat package ICs, on a transported board, a reference point is marked on the board surface and the position of this mark is Recognized,
After correcting the mounting position of the component, the component was mounted on the board. However, in order to increase the density of component mounting on a miniaturized board, there is no space to provide the reference mark on the board surface, and when the reference mark is provided, a mounting pattern must be placed close to the periphery of the reference mark. This poses a problem in that it becomes impossible to do so, and that part becomes a dead space, which hinders the increase in component mounting density.

[Object of the Invention] This invention has been made in view of the above-mentioned circumstances, and its purpose is to eliminate the need for providing reference marks on the board surface.
An object of the present invention is to provide a method for recognizing the position of a printed circuit board, which enables high-density mounting of components on a circuit board and also enables mounting of components that require a high degree of mounting accuracy.

[Summary of the Invention] In order to achieve the above-mentioned object, the present invention has a board that has been transported and has been stopped at a component loading position, and a pattern of the same shape is selected from each side of a rectangular real pattern formed on the board. Assuming a reference pattern of a shape, a camera for image processing measures the distance from a point arbitrarily set on each side of the reference pattern to a point where a perpendicular to each corresponding side of the actual pattern intersects. This measurement data is processed by the CPU to calculate the amount of displacement of the component mounting center point on the actual pattern in the X-axis, Y-axis, and rotational direction, and based on this displacement data, the component is mounted on the board. The main point is that after the mounting robot that holds the component moves to the corrected component mounting position, the mounting robot places the component on the substrate.

[Example] Hereinafter, an example of the present invention will be described with reference to the drawings. This example shows the case where components are mounted on a predetermined position on a board that has been transported, and the outline will be explained as follows.
After a board transported by a conveyor or the like is positioned at a component mounting position, the parts held by a mounting robot are mounted at a predetermined position on the board. Z in the figure is a reference pattern, and Z' in the figure is an actual pattern indicating the position of the pattern on the substrate that has been transported and positioned. Then, the position of the actual pattern Z' is measured by an image processing camera, and the measured position is compared with a reference position to determine the amount of displacement. The method for determining this amount of displacement will be explained in sequence.

FIG. 1 shows the relationship between the reference pattern Z and the actual pattern Z'.

The reference pattern Z is the origin O (0°0) of the x and y axes, point A on the x axis (Lx, O), point 0 on the y axis (0, L,), and B
The actual pattern Z' is a rectangle whose apex is the point (LX, Ll), and the actual pattern Z' is a rectangle whose apex is the point 0'A'B'C'. Then, set points p(o, L
vl), Q(LX, Ly2), R(Lyl, O)
, S (LX2, Ly) is the actual pattern Z'
The points that intersect with the corresponding sides of are the points P', Q', R', S
', and the respective distances are DXI, Dy2, D, l, Dy2
Then, the coordinates of points P', Q', R', and S' are (Dx+
,L,1),(LylDx2,L v2),(Lyl,
D, 1), (LX2, L, +D112).

Assuming that the angular displacement amount of pattern Z' with respect to pattern Z is Δ0.

Equation of straight line 0'A' % Formula %) Equation of straight line A'B' V =-cot△θ(x-Lx-[1x2)+Ly? (
sin△θ=0) Equation of straight line B'C'
θ=0) Find the coordinates of points 0' and B' from the above straight line equation, find the length of straight line 0'B', and find the similarity ratio KS of the actual pattern Z' to the reference pattern 2. , where A=(LX2-Lyl)tan2△0 +(Ly2-L
yl−Ly−Dy2”Dy1)tanΔθ+(LX+I
]X2-I]X1).

The angular displacement amount Δ0 of pattern Z' with respect to pattern Z
is calculated using the following formula.

Also, the coordinates of the mounting center point in the reference pattern Z are (
L x p , L V p ), then y with respect to the point L' of the component mounting center point of the actually positioned board
The displacement amounts DX and Dy in the axis and y-axis directions are as follows.

Dx Misaki Dx+ +Lxp X(Ks-1)-LypX
tanΔθ・old...(2) Dy = Dyl + L
ypX (Ks-t)+t, XpX tanΔθ
(3) Next, the block diagram shown in FIG. 2 will be explained.

The camera 1 for image processing moves to the vicinity of the set points P, Q, R, and S on each side of the reference pattern Z, and images the corresponding points P', Q', R', and S' of the actual pattern Z'. The processing section 2 is a straight line P
Distance 1i11Dx+ of P', QQ', RR', QQ',
When Dx2, D y I, and D y 2 are measured and the data is input to the CPU 3, the CPU 3 receives the above (1).
, (2), (3) are stored, and L
xp, Lyp, Lx, Ly, Lx+, Lx2, Lllll
, Ly2 data is input, and the data of the Dxl, DX
2. By inputting Dyl and Dy2, the CPU 3 calculates the displacement Dx, Dy and the angular displacement Δθ of the actually positioned component mounting center point L' of the board in the y-axis, y-axis directions, and the data is sent to NC device 4.5.6,
The NC device 4.5.6 moves the mounted robot (not shown) to accurately place the parts held by the mounted robot on the board 7.
be mounted on top. Once loading is complete, the loading robot returns to its home position and waits for the next task.

On the other hand, the actual pattern image of the substrate positioned from the image processing unit 2 and the distances Dxl, Dx2, Dyl, Dy2,
Furthermore, data such as displacement amounts DX, Dy, Δ0, etc. are displayed on the cathode ray tube 9 by the CRT controller 8 in response to signals from the CPU 3.

Furthermore, the processing steps within the CPUa will be explained in detail with reference to the flowchart shown in FIG. Note that the camera 1 is installed adjacent to a head section of a mounting robot (not shown) that includes a component holding section. Also, the flowchart will be explained in six steps.

(2) Step The NC device 4.5.6 receives a signal from the CPU 3 and is located at the origin (not shown) of each of the y-axis, y-axis, and 0-axis of the mounted robot.

■Step The NC device 4.5.6 is activated by the signal from the CPU 3, and the camera l moves from the origin to the set point P of the reference pattern Z.
The point P' of the actual pattern Z' is projected, and the image processing section 2 converts it to PP.
The distance #DX1 between ' is measured, and the data is sent to the CPU 3.
to be displayed.

(2) Step Repeat the same operation as for the point P in the order of points Q, R, and S.

■Step CPU3 is the distance D between PP', QQ', RR', 551
By receiving data of x I, Dx2, Dyl, Dy2, position correction calculation is performed and displacement amounts Dx, Dy, Δ
Calculate θ.

■Step CPU 3 displays the correction data DX, D, . and move it to the position corrected by Dx, Dy, and ΔX.

(2) The step mounting robot mounts a component held by, for example, a suction nozzle onto a substrate 7'' according to a signal from the CPU 3. Once the loading is complete, the camera l installed on the head of the loading robot will be
Returns to the origin by the signal from PU3.

In addition, to outline the operation of the mounting robot, 1. The mounting robot is located at the origin of the NC system, and 2. At this origin, it holds the parts to be mounted on the board 7.

3. After moving to points P, Q, R, S in order, the displacement DX
, D, , to the position corrected by Δθ.

4. Mount the component on the board 7 at this corrected position.

5. After this installation is completed, set the origin of the NC system, that is, 11
Return to

As described above in detail, the camera 1 for image processing allows perpendicular lines from points P, Q, R, and S set on each side of the rectangular reference pattern Z to be connected to each corresponding point in the actual pattern Z'. The distances to the points P', Q', R', and S' that intersect with the sides are measured, and based on the data of the distances Dxl, DX2, D, I, D, and 2, the CPU 3 calculates the actual pattern Z with respect to the reference pattern Z. After taking into account the similarity ratio KS with L', the displacement DX, D, , Δθ between the mounting center point of the component and L' is calculated, and the signal from the data is used to control the NC device 4.5.6.
is moved to a position where the displacement amounts Dx, DV, and Δθ have been corrected, so the accuracy of the component mounting position can be greatly improved.

Further, any pattern may be used as long as the pattern of the substrate 5 forms a rectangle, and as shown in FIG. A similar effect can be obtained if the extension lines of the pattern form a rectangle. Furthermore, as shown in Figure 5,
The same thing can be done if a rectangle is formed by using an arbitrary point pattern 11 located on the intersection of two adjacent patterns of a rectangle and its diagonal, and considering a straight line passing through this point pattern 11 and parallel to the two patterns described above. obtain the effect of In the case of Fig. 5, the side set points P and R
is in the same position as O.

In the present invention, the reference pattern Z is considered to be a rectangle, but it is obvious that it can be applied to a quadrilateral of any shape as long as the four interior angles are known.

"Effects of the Invention 1 and Below"-1 As described in detail, according to the present invention, each side of a rectangular real pattern formed on a board that has been transported, stopped at a component loading position, and positioned F is Assuming a rectangular reference pattern of the same shape, image processing is performed to calculate the distance from a point arbitrarily set on each side of the reference pattern to the point where the perpendicular to each corresponding side of the actual pattern intersects. This measurement data is sent to the CPU
The mounting robot processes the actual pattern by calculating the amount of displacement in the X-axis, Y-axis, and rotational direction of this component mounting center point, and holds the component to be mounted on the board based on this displacement data. However, after moving to the corrected component mounting position, this mounting robot can place the component on the board, so there is no need to specially attach a reference mark within the surface of the board. Since image processing by the camera can be performed using the normal pattern of , it is possible to improve the component mounting density of this board.

Furthermore, from such measurements, it is possible to calculate the X-axis, Y-axis directions, and angular displacements that take into account the similarity ratio of the actual pattern to the reference pattern. (The board has passed the pre-inspection) is also taken into consideration, and mounting accuracy can be improved.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing the relationship between an actual pattern and a reference pattern according to an embodiment of the invention, FIG. 2 is a block diagram of an embodiment of the invention, and FIG. 3 is a flowchart showing processing steps in the CPU. , 4 and 5 are plan views of the corrected actual pattern. l...Camera, 3...CPU, 4.5
．． 6... NG device, 7... Substrate, 10
... Line pattern, 11 ... Point pattern, Dx, Dy, △0 ... Displacement amount, Z ...
・Reference pattern, Z'...... Turn to implement. Patent Applicant: Yamagata Casio Co., Ltd. Same as above Casio Computer Co., Ltd. Agent Patent Attorney: Machi 1) Tadashi Toshi: 、、、、、、、：

Claims (1)

[Claims] A rectangular reference pattern of the same shape is assumed from each side of the rectangular actual pattern formed on the board that has been transported and stopped at the component mounting position, and a pattern is arbitrarily applied to each side of the reference pattern. The distance from the set point to the point where the perpendicular lines to the corresponding sides of the actual pattern intersect is measured using an image processing camera, and this measurement data is converted to CP.
U processing, calculating the amount of displacement of the component mounting center point on the actual pattern in the X-axis, Y-axis, and rotational direction, and holding the component to be mounted on the board based on the data of the displacement amount. A method for recognizing the position of a printed circuit board, characterized in that the robot moves to a corrected component mounting position, and then the mounting robot places the component on the board.