JPH02234005A - Detecting method for position of feature part of object - Google Patents

Abstract

PURPOSE:To exactly detect the position of a feature part by detecting the position of a point in which a limit value of an area of a superposed part or a non-superposed part is shown. CONSTITUTION:A substrate 1 is provided on an XY direction moving device 5 consisting of XY tables 3, 4, and when this device 5 is driven, the substrate 1 moves in the X and the Y directions. In this state, by setting an origin O of X and Y coordinates as a start point, and observing the outside periphery of electronic parts 2 by a camera 6, its X and Y coordinates are detected. This contour can be detected simply by a binarization processing part 13 since luminances of the substrate (white) 1 and the parts (black) 2 are different. Subse quently, an area S of a superposed part in which a feature part detecting circle area of the parts 2 and a peripheral edge part of the parts 2 are superposed is calculated by a superposed area calculating part 14. By deriving a limit value (minimum value) of this area S, a position of the feature part can be derived.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to a method for detecting the position of a characteristic part of an object, in which an area for detecting the characteristic part of the object is set within the field of view of a camera, and The position of the characteristic part of the object is detected by calculating the limit value of the overlapping area or non-overlapping area of the object. (Prior art) For example, IC chips, LSI chips, resistor chips. Pattern matching is a well-known method for inspecting whether electronic components such as capacitor chips are mounted in the correct position on a board. FIGS. 8 and 9 show a conventional pattern matching method. First, as shown in FIG. Put it in the set check areas A1 to A4 and observe it, and check the corners of the reference image 100 and each area AI-A.
Angle k a - k d of the superimposed part a w d where 4 overlaps
Find the coordinates of . Next, Figure 9. As shown in the figure, each area A1 to A4 is relatively x
By moving in the y direction, each superimposed part a w d is the image 101
Find the matching position that most overlaps with the corner of , consider the coordinates of the angle Ka % K d at that position as the coordinates of the angle Ka"'-Kd" of the image 101, and calculate each corner Ka -
From the XY coordinate values of K d, positional deviation ΔX. Δy and θ were calculated. (Problem to be Solved by the Invention) However, in the above conventional method, the reference image 100
The corner of the image 101 to be inspected does not easily overlap with the corner of the image 101 to be inspected, and there is a problem in that the inspection accuracy cannot be improved accordingly.

Therefore, an object of the present invention is to provide a means for accurately detecting the position of a characteristic part of an object, such as a corner. (Means for Solving the Problems) For this purpose, the present invention observes the outer periphery of an object with a camera, detects the outline of this object, and then sets a feature detection area within the field of view of the camera. is moved along the above contour, and the area of the overlapping part where this feature detection area and the peripheral edge of the object overlap or the area of the non-overlapping part where they do not overlap is calculated, and the area of this overlapping part or non-overlapping part is calculated. By detecting the position of the point where the limit value of appears, the position of the characteristic part of the object is detected. (Operation) According to the above configuration, the position of a characteristic part of the object such as a corner is detected by calculating the position of the point where the maximum value of the area of the overlapping part or the non-overlapping part appears. l》 Next, an embodiment of the present invention will be explained by taking as an example a visual inspection means for detecting positional deviation of electronic components mounted on a board. Substrate, 2
is an electronic component mounted on board l. Substrate l is XY
The substrate 1 is disposed on an XY direction moving device 5 consisting of tables 3 and 4, and when this device 5 is driven, the substrate 1 is moved in the XY directions. An appearance inspection camera 6 such as a COD area camera or a linear image camera is provided above the substrate 1, and a light source 7 and a condensing element 8 are provided diagonally above the substrate 1. IO is a control unit connected to the camera 6, which includes a D/A converter 11, a frame memory 12.2 {t1 conversion processing unit 13. It consists of a superimposed area calculation section 14, a CPU 15, etc. FIG. 2 shows how the outline of the electronic component 2 is tracked by scanning with the above device. In the figure, 2
0 is the field of view of the camera 6, and 2 is the electronic component mentioned above. As shown by the wavy arrow, the outer circumference of the electronic component 2 is observed starting from the origin 0 of the XY coordinates, and the XY coordinates of its outline are determined. Since the brightness of the board (white) 1 and the electronic component (black) 2 are different, the contour can be easily detected by a binarization processing means. Note that this type of contour tracking means is well known. After contour tracking is completed as described above, the scanning shown in FIG. 3 is then performed using an arbitrary point (for example, the intersection of the electronic component 2 and the positive side of the Y-axis) as a starting point. In the figure, A is field of view 2
0, and move this area A along the contour detected by the contour tracking means to detect the area A and the peripheral edge of the electronic component 2. The area S of the superimposed part (shaded part) a where
Calculate. Figure 4 shows the calculation results, and in the figure, SO
is the area of area A, and Φ~■ are the positions of each point in Figure 3. When area A is moved along a line bisected by the contour, the area of superimposed part a is SO/2 in the part along the straight line part of electronic component 2, but in the corner part, that is, in the characteristic part. ■、■． In ■ and ■, the limit value (minimum value) is So/4. Therefore, these points ■, ■.
By determining the XY coordinates of ■ and ■, the characteristic part (corner)
can detect the position of

Once the coordinates of the characteristic parts ■ to ■ have been obtained in this way, the coordinates of the center O° of the electronic component 2 are calculated, and the positional deviation ΔX, Δy of the electronic component 2 in the x and y directions (see Fig. 3) You can easily know. Also, the error θ in the rotation direction can be easily calculated. Note that in the above method, the coordinates of the characteristic parts ■ to ■ are determined by determining the limit value (minimum value) of the area S of the overlapping part a, but the area of the non-overlapping part b in the area A (So-
It is the same thing to find S), and in this case, the non-overlapping part b
The point where the area of is the maximum is the position of feature parts ■～■. (Embodiment 2) In FIG. 5, 3 is a mini-transistor having three terminal portions 3a, 3b, and 3c. This one is also the same as the above 1st
As in the case of the embodiment, after contour tracing is performed along the outer periphery to determine the coordinates of the contour, the feature detection area A is moved along this contour to determine the area S of the superimposed portion a. ．． Figure 6 shows the results, and by finding the coordinates of the point Φ~[phase] where the limit values (maximum and minimum values) appear, the position of the feature can be found.
As described above, according to the present method, the coordinates of a feature such as a corner can be accurately determined regardless of the shape of the object.

(Example 3) FIG. 7 shows a case where this method is applied to a rotary head type electronic component mounting apparatus.

3l is a rotary head, 32 is a large number of transfer heads vertically installed along the outer periphery of the hesode 31, 33 is a nozzle thereof, 3
4 is a substrate positioned on the XY direction moving device 35; 36;
is a support stand, 6 is the above-mentioned camera provided on this support stand 36, and P is an electronic component. This device sucks and takes up the electronic component P to the lower end of the nozzle 33 in a chip supply section (not shown) while rotating the rotary head 31 around its axis at a pitch, and the rotary head 3l. Along with the rotation,
This electronic component P is mounted on a board 34. A camera 6 is provided between the chip supply section and the substrate 34, and the nozzle 3
By observing the electronic component P sucked by the electronic component P from below, the positional deviation ΔX, Δy. Detect θ. Then, by driving the XY direction moving device 35 to move the substrate 34 by the same amount in the XY directions, the positional deviation ΔX. By correcting Δy and rotating the nozzle 33 in the θ direction around its axis by a motor (not shown), the error θ in the rotational direction is corrected, and then the electronic component P is mounted on the board '34. , the errors ΔX, Δy, and θ can be corrected and mounted on the board 34. This method can also be used in various fields, such as detecting characteristic parts of circuit patterns printed on circuit boards, and the target object may be other than electronic components. be. (Effects of the Invention) As explained above, the present invention observes the outer periphery of an object with a camera, detects the outline of this object, and then detects the feature detection area set within the field of view of the camera. Move along the contour, calculate the area of the overlapping part where the feature detection area and the peripheral edge of the object overlap, or the area of the non-overlapping part where they do not overlap, and calculate the limit of the area of the overlapping part or the non-overlapping part. By detecting the position of the point where the value appears,
Since the position of the characteristic part of the object is detected,
It is possible to accurately detect the position of the characteristic part of the target part, such as the corner of an electronic component.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, in which Fig. 1 is a perspective view of an external appearance inspection device, Figs. 2 and 3 are plan views during inspection, Fig. 4 is a characteristic diagram, and Fig. 5 is a perspective view of an external appearance inspection device. Plan view of another embodiment, No. 6
The figure is a characteristic diagram, FIG. 7 is a partial side view of a rotary head type electronic component mounting apparatus, and FIGS. 8 and 9 are plan views of conventional means. 2.3. P...Target 6...Camera 20...Camera field of view A...Characteristic detection area a...Overlapping part b/Non-overlapping part

Claims (1)

[Claims] After observing the outer periphery of the object with a camera and detecting the outline of the object, a feature detection area set within the field of view of the camera is moved along the outline, and the feature detection area is By calculating the area of the overlapping part where the peripheral edge of the object and the object overlap, or the area of the non-overlapping part where they do not overlap, and detecting the position of the point where the maximum value of the area of the overlapping part or the non-overlapping part appears, A method for detecting the position of a characteristic part of an object, the method comprising detecting the position of a characteristic part of an object.