JP6246775B2 - Bonding wire detection device and bonding wire detection method - Google Patents

Description

  The present invention relates to a bonding wire detection device and a bonding wire detection method for three-dimensionally detecting bonded wires.

  When inspecting the appearance of a wire of an electronic component subjected to wire bonding as shown in FIG. 7, the wires 100 and 101 are accurately recognized one by one, and the shape of the wire and the contact between the wires are inspected. There are things to do. As a method for recognizing a wire, there is a method described in Patent Document 1.

  The wire recognition method described in Patent Document 1 captures a wire from a plurality of directions, combines them, and displays them three-dimensionally. If a user wants to recognize a specific wire, the user clicks on the wire to be recognized and zooms in on the wire.

JP 2006-147808 A

  By the way, as shown in FIG. 7, the wires 100 and 101 may be three-dimensionally crossed up and down, and the adjacent wire may enter the image area of the wire to be specified. In such a case, in the method described in Patent Document 1, it is necessary to photograph the wire from a plurality of directions while taking into account the overlapping of the wires, and it takes time and effort to photograph. In addition, when a user wants to recognize a specific wire, the user needs to click the wire to be recognized while visually checking the three-dimensional image, and one wire cannot be accurately and automatically tracked. .

  Therefore, in view of such circumstances, the present invention intends to provide a bonding wire detection device and a bonding wire detection method capable of accurately tracking the wires to be detected one by one.

The bonding wire detection device of the present invention is a bonding wire detection device that three-dimensionally detects a wire bonded to a connection surface, and is relatively close to and away from the bonded wire, and has a different focus. An imaging unit that captures a plurality of images of the wire, and in the acquired image, a region of one connection surface to which one end of the wire is connected and a region of the other connection surface to which the other end of the wire is connected Doo and connecting surface area specifying means for specifying, based on the position of the region of the two connecting surfaces identified by the connection surface area specifying means, and start and end points calculating means for calculating a position of the tracking start and end points, from the obtained different respective image focus degree three-dimensional distribution of imaging plane focus degree distribution representing the focus degree distribution is stored which indicates a high pixel positions focus degree with respect to the focal by the imaging means, before A longitudinal section focus degree distribution forming means for forming the approach and spacing direction and said longitudinal section focus degree distribution focus distribution, was cut on the vertical plane in the direction of the cross section perpendicular to the straight line connecting both connection surfaces Positions from the tracking start point to the end point calculated by the start point / end point calculation means based on the longitudinal cross-section focus degree distribution corresponding to each position at positions spaced apart by a predetermined interval within the range of one wire By tracking a location with a high degree of focus, the trajectory from one connection surface to which one end of one wire is connected to the other connection surface to which the other end of the wire is connected And tracking means for tracking.

  According to the bonding wire detection apparatus of the present invention, a plurality of images with different focused pixel positions are acquired by the imaging means. The longitudinal section focus degree distribution forming unit can extract the focus degree distribution on a certain longitudinal section from the three-dimensional distribution of the focus degree to form the longitudinal section focus degree distribution. The longitudinal cross-section focus degree distribution is a representation of the focus degree distribution in the cross section in the approach and separation directions between the imaging means and the wire. The tracking means tracks a portion with a high degree of focus at positions spaced apart by a predetermined interval within the range of one wire with reference to the longitudinal cross-section focus degree distribution corresponding to each position. As a result, it is possible to trace a single wire by tracking a location with a high degree of focus, assuming that a location with a high degree of focus is the position of the wire. Can be tracked automatically.

  The said structure WHEREIN: You may provide the tracking image preparation means which produces the tracking image which made the said several vertical cross-section focus degree distribution continuous. This makes it easy to trace a single wire.

  The tracking unit may include a virtual tracking unit that performs virtual tracking when there is no portion with high focus degree in the middle of tracking in the longitudinal section focus degree distribution. The virtual tracking unit can perform tracking by so-called motion tracking.

The bonding wire detection method according to the present invention is a bonding wire detection method for three-dimensionally detecting a wire bonded to a connection surface, and is relatively close to and away from the bonded wire to have different focal points. Take multiple images of the wire, and in the acquired image, identify the area of one connection surface to which one end of the wire is connected and the area of the other connection surface to which the other end of the wire is connected and, based on the position of the region of the two connecting surfaces identified, tracked start point and calculates the position of the end point, focus degree indicating the acquired high pixel positions of focus for different respective image focal From the focus degree three-dimensional distribution in which the imaging surface focus degree distribution representing the distribution is stored, the focus degree is on the vertical cross section which is a cross section in a direction perpendicular to the straight line connecting the connecting and connecting directions. Distribution cut out And longitudinal section focus degree distribution is formed at a position spaced a predetermined distance within the range of one wire, based on the vertical sectional focus degree distributions corresponding to the respective positions, the end point from the calculated track start point By tracking a location with a high degree of focus up to the position of, from one connection surface where one end of one wire is connected to the other connection surface where the other end of the wire is connected It tracks the trajectory.

  A tracking image in which a plurality of the longitudinal cross-section focus degree distributions are continuous may be created, or in the vertical cross-section focus degree distribution, virtual tracking may be performed when the high part in the middle of tracking does not exist.

  In the present invention, even if the wires are dense, the wires to be detected can be accurately tracked one by one.

It is a block diagram which shows the detection apparatus of the bonding wire of this invention. It is a figure which shows the image of the wire and connection surface which were imaged by the imaging means. It is a figure which shows the longitudinal cross-section focus degree distribution in A, B, C, D of the said FIG. It is a conceptual diagram which shows the tracking method by a tracking means. It is a flowchart figure which shows the procedure of the detection method of the bonding wire of this invention. It is a figure which shows the longitudinal cross-section focusing degree distribution in A, B, C, D of the said FIG. 2, and shows the tracking method by a virtual tracking part. It is a simplified top view which shows the state where several wires were densely connected to the connection surface.

  Hereinafter, embodiments of the present invention will be described with reference to FIGS.

  The bonding wire detection apparatus of the present invention detects a bonded wire in a three-dimensional manner when a wire tip is bonded (bonded) to a pattern portion such as an electronic component or a circuit board terminal. .

  As shown in FIG. 1, the bonding wire detection apparatus of the present invention includes an image pickup means 1, a memory 10, a connection surface area specifying means 2, a calculation means 3, and a longitudinal section focusing provided in a computer (not shown). A degree distribution forming unit 4, a tracking image creating unit 5, and a tracking unit 6 are provided. Further, display means (monitor) (not shown) is connected to the computer.

  The imaging means 1 is composed of a CCD camera or the like, and acquires an image including a wire 20 that is an imaging object and a connection surface (bonding surface) 21. The imaging means 1 can move in the z direction (up and down direction) and can approach and separate from the wire 20 and the connection surface 21 relatively. That is, the imaging unit 1 changes the distance to the imaging object and acquires a plurality of images 22 (see FIG. 2) that are different in focus in the vertical direction (acquires images with different focused pixel positions). . In FIG. 2, all the positions of the image 22 are in focus, but actually, one image is in focus only at one of the positions.

  The connection surface area specifying unit 2 specifies the area of the connection surface to which the wire is connected in the acquired image. Specifically, the image 22 as shown in FIG. 2 is displayed on the display means, and the range of the connection surface region 31 in the image 22 as shown by the dotted line in FIG. 2 by the user dragging the mouse, for example. Is specified and specified, the connection surface area specifying means 2 stores the specified range.

  The calculation means 3 performs various calculations necessary for tracking one wire. The calculation means 3 includes a start point / end point calculation means 7 and a focus degree calculation means 8.

  The start point / end point calculation means 7 calculates and stores the positions of the tracking start point and end point by the tracking means 6 based on the positions of the two connection surface areas 31a and 31b designated by the connection surface area specifying means 2. It is.

  The focus degree calculation means 8 includes an imaging surface focus degree distribution generation means 11 and a focus degree three-dimensional distribution generation means 12. For each image, there is a pixel position with a high degree of focus (a pixel position in focus), and the pixel position is different for each image. The imaging surface focus degree distribution generation means 11 of the focus degree calculation means 8 generates an imaging surface focus degree distribution for each image acquired by the imaging means 1. The imaging surface focusing degree distribution represents the focusing degree distribution on the imaging surface at a certain imaging position. The in-focus degree three-dimensional distribution generating unit 12 of the in-focus degree calculating unit 8 can obtain the in-focus degree three-dimensional distribution by sequentially storing the in-focus degree distributions in the order of photographing positions.

  The vertical cross-section focus degree distribution forming unit 4 generates a focus degree distribution on a vertical cross section from the focus degree three-dimensional distribution stored in the focus degree three-dimensional distribution generating unit 12 of the focus degree calculating unit 8. Cutting out and forming a longitudinal section focusing degree distribution. The longitudinal cross-section focus degree distribution expresses the focus degree distribution in a cross section (see FIG. 4) in the approach and separation direction (z direction in the present embodiment) between the imaging unit 1 and the wire 20. Examples of the longitudinal cross-section focusing degree distribution are shown in S (A), S (B), S (C), and S (D) of FIG. For example, the longitudinal cross-section focus degree distribution S (A) in FIG. 3 is formed by the focus degrees at all pixel positions corresponding to the positions on the line A in FIG.

  The vertical cross-sectional focus degree distribution at the cross-sectional position A in FIG. 2 corresponds to S (A) in FIG. Similarly, the longitudinal cross-sectional focus degree distribution at the cross-sectional position B in FIG. 2 corresponds to S (B) in FIG. 3, and the vertical cross-sectional focus degree distribution at the cross-sectional position C in FIG. 2), the vertical cross-sectional focus degree distribution at the cross-sectional position D in FIG. 2 corresponds to S (D) in FIG. In FIGS. 2 and 3, the vertical cross-sectional focus degree distribution shows only four locations of the cross-sectional positions A, B, C, and D, but actually, from one connection surface 21 a (cross-sectional position A) to the other. An infinite number of longitudinal section focus degree distributions can be formed over the connection surface 21b (cross-section position D).

  As shown in FIG. 2, when another wire 22 crosses above the wire 20 to be tracked, as shown in FIG. 3, the longitudinal section focus degree distributions S (A) and S (B) are in focus. There are points 40 and 42 which are high-degree places, and a line 41 (41a) which is a high-focus position, and the vertical cross-section focus distribution S (C) is a high-focus position. 40 and 42 exist, and the vertical cross-section focus degree distribution S (D) includes points 40 and 42 that are places with a high degree of focus and a line 41 (41b) that is a place with a high degree of focus.

  The tracking image creating means 5 corresponds to each of the positions A, B, C, and D at positions separated by a predetermined interval within the range of the single wire 20 (positions A, B, C, and D in FIG. 2). A tracking image is created based on the vertical cross-section focusing degree distribution (S (A), S (B), S (C), S (D) in FIG. 3). That is, the tracking image creation means 5 creates a tracking image in which the vertical section focusing degree distribution S (A) corresponding to the tracking start point to the vertical section focusing degree distribution S (D) corresponding to the tracking end point are continuously generated. To do. In this embodiment, a moving image is used as the tracking image. When this moving image is displayed by the display means, the user can visually track the wire.

  The tracking unit 6 sequentially tracks locations with high degrees of focus based on the tracking image. That is, the tracking means 6 scans the longitudinal cross-section focus degree distributions S (A) to S (D) from the start point A to the end point D as indicated by the arrows in FIG.

  A bonding wire detection method using the bonding wire detection apparatus of the present invention will be described with reference to the flowchart of FIG.

  The imaging unit 1 acquires a plurality of real images having different focal points in the vertical direction so that the wire 20 and the connection surface 21 are within the imaging range (step S1). As a result, a plurality of image data with different focused pixel positions are stored in the memory 10. In this embodiment, as shown in FIG. 2, a wire 20 (wire to be tracked) connected to one connection surface 21a and the other connection surface 21b and another wire 22 intersecting above the wire 20 A case of shooting will be described.

  Next, as shown in FIG. 2, the connection surface area specifying means 2 specifies the connection surface areas 31a and 31b in any of the captured images 22 (step S2). Specifically, in the first method, one connection surface 21a to which one end of the wire 20 is connected in the image 22, as indicated by a dotted line in FIG. The connection surface region 31b corresponding to the other connection surface 21b to which the other end of the wire 20 is connected is specified. Thereby, the connection surface area specifying means 2 stores the designated range. In the second method, the connection surface area is automatically specified based on the information stored in advance by the first method. For example, there are the following methods for automatically specifying the connection surface area. In the image 22, a pattern or an object existing at a position away from the connection surface is set as a mark, and a relative position between the connection surface area and the mark is stored in advance in the computer. By finding the mark in the image 22 in the subsequent shooting, the connection surface area can be automatically specified from the stored relative position information.

  The start point / end point calculation means 7 calculates and stores the tracking start point and end point positions based on the positions of both the connection surface areas 31a and 31b designated by the connection surface area specifying means 2 (step S3).

  Further, the imaging surface focus degree distribution generation means 11 of the focus degree calculation means 8 generates an imaging surface focus degree distribution in each image from the image data stored in the memory 10 (step S4). The focus degree three-dimensional distribution generation means 12 of the focus degree calculation means 8 obtains the focus degree three-dimensional distribution by sequentially storing the imaging surface focus degree distribution in the order of the photographing positions.

  The vertical cross-section focus degree distribution forming unit 4 generates a focus degree distribution on a vertical cross section from the focus degree three-dimensional distribution stored in the focus degree three-dimensional distribution generating unit 12 of the focus degree calculating unit 8. The vertical section focusing degree distribution as shown in FIG. 3 is formed (step S5). At this time, as shown in FIG. 2, the longitudinal cross-section focusing degree distribution forming means 5 is in the z direction and in a direction orthogonal to the straight line L connecting the connection surfaces 21a and 21b (the dotted lines A, B, and C in FIG. , D direction), the longitudinal section focus degree distributions S (A) to S (D) as shown in FIG. 3 are formed. 2 and 3, the vertical cross-section focusing degree distribution shows only four positions of cross-sectional positions A, B, C, and D, but in reality, one of the connection surfaces 21a (the cross-sectional position A serving as the starting point). Innumerable longitudinal cross-section focusing degree distributions can be formed over the other connecting surface 21b (cross-sectional position D as an end point).

  The tracking image creating means 5 has a vertical cross-section focus degree distribution (figure 2) corresponding to a plurality of wire positions (positions A, B, C, and D in FIG. 2) at a predetermined interval within the range of one wire 20. The tracking image is created with reference to S (A), S (B), S (C), S (D)) in step 3 (step S6). At this time, the user can set the predetermined interval. That is, it is possible to set at what interval from the one connection surface 21a to the other connection surface 21b how to create a tracking image using the longitudinal section focusing degree distribution. If the interval is short, a tracking image is created with a large number of longitudinal section focus degree distributions, and if the interval is long, a tracking image is created with a small number of longitudinal section focus degree distributions.

  Based on the tracking image, the tracking unit 6 sequentially tracks a portion having a high degree of focus from the portion corresponding to the one connection surface 21a to the portion corresponding to the other connection surface 21b. Step S7). That is, as shown by the arrow in FIG. 4, the longitudinal cross-section focusing degree distribution is scanned from the start point A to the end point D. Specifically, in S (A) of FIG. 3, the line 41 (41 a), which is a location with a high degree of focus, corresponds to the one connection surface 21 a, and a location with a high degree of focus in contact with the connection surface 21 a. Is recognized as corresponding to the wire 20 connected to the connection surface 21a. Then, the trajectory of the point 40, which is a location with a high degree of focus, is tracked in order of the longitudinal section focus degree distributions S (B) and S (C). And in S (D) of FIG. 3, the line 41 (41b) which is a location with a high focus degree is corresponding to the other connection surface 21b, and it is a location with a high focus degree which touches this. 40 is recognized as corresponding to the wire 20 connected to the connection surface 21b. In this manner, assuming that a portion with a high degree of focus is the position of the wire, a single wire can be traced by tracking a portion with a high degree of focus.

  The bonding wire detection apparatus and the bonding wire detection method of the present invention focus on the longitudinal sections corresponding to the respective positions A, B, C, and D that are separated by a predetermined distance within the range of one wire 20. Based on the degree distributions S (A), S (B), S (C), and S (D), the location 40 with a high degree of focus is tracked. As a result, assuming that the portion 40 with a high degree of focus is the position of the wire 20, if the portion 40 with a high degree of focus is tracked, one wire 20 can be automatically tracked, so that the wires are densely packed. Even if it is, the wire 20 used as a detection target can be tracked correctly.

  The tracking unit 6 may include a virtual tracking unit (not shown). The virtual tracking unit performs virtual tracking when there is no portion 40 with high focusing degree in the middle of tracking in the vertical section focusing degree distribution. That is, the virtual tracking unit performs motion tracking of the portion 40 with a high degree of focus during tracking. Motion tracking is to analyze the movement of an object using a specific mark or pattern in a screen (image) as a target. For example, as shown in FIG. 6, in the longitudinal cross-section focus degree distribution S (B), when there is no portion 30 with high focus degree in the middle of tracking, the virtual tracking unit performs motion tracking as indicated by an arrow. Virtual tracking is performed assuming that there is a location 30 with a high degree of focus.

  As described above, the embodiments of the present invention have been described. However, the present invention is not limited to the above-described embodiments, and various modifications can be made. For example, the imaging unit 1 is not limited to a CCD camera, and various other devices such as a CMOS camera can be used. Can be adopted. As the imaging direction, the imaging unit 1 is located above the imaging object and the imaging unit 1 moves up and down. However, the imaging unit 1 is positioned in the horizontal direction with respect to the imaging object, and the imaging unit 1 is You may move horizontally. Alternatively, the imaging unit 1 may be fixed and the imaging object side may approach or separate from the imaging unit 1. The tracking image may not be a moving image but may be a collection of a plurality of still images. In this case, accurate tracking can be performed by acquiring the longitudinal cross-section focus degree distribution at short intervals and performing tracking based on a large number of vertical cross-section focus degree distributions. In the above embodiment, the tracking image is created at four locations (four longitudinal section position information), but the number of longitudinal section focusing degree distributions can be arbitrarily set. Further, when creating a tracking image, the acquisition positions of the longitudinal cross-section focusing degree distribution need not be equal. For example, the longitudinal cross-section focus degree distribution is acquired at a short interval at a place where the wire is likely to be dense, and the longitudinal cross-section focus degree distribution is obtained at a long interval at a place where the wire is not likely to be dense. May be obtained to create a tracking image. Further, it is not necessary to form the longitudinal cross-section focus degree distribution with all the captured images, and the vertical cross-section focus degree distribution may be formed with only a part of the captured images.

DESCRIPTION OF SYMBOLS 1 Image pickup means 4 Longitudinal section focusing degree distribution formation means 5 Tracking image creation means 6 Tracking means 20 Wire 21 Connection surface 22 Image 30, 31, 32, 40, 41, 42 High focus L location Straight line S Longitudinal section alignment Strain distribution

Claims (6)

A bonding wire detection device for three-dimensionally detecting a wire bonded to a connection surface,
An imaging means for capturing a plurality of images of wires with different focal points by approaching and separating from the bonded wires;
In the acquired image, a connection surface region specifying means for specifying a region of one connection surface to which one end of the wire is connected and a region of the other connection surface to which the other end of the wire is connected;
Based on the position of the region of the two connecting surfaces identified by the connection surface area specifying means, and start and end points calculating means for calculating a position of the tracking start and end points,
From the in- focus degree three-dimensional distribution in which the in-focus degree distribution representing the in- focus degree distribution indicating the pixel position having a high in-focus degree is stored for each image with different focus obtained by the imaging means , A longitudinal cross-section focus degree distribution forming means for forming a vertical cross-section focus degree distribution obtained by cutting out a focus degree distribution on a vertical cross section that is a cross section in a direction perpendicular to a straight line connecting both the connecting surfaces in the approaching and separating directions ; ,
From the tracking start point calculated by the start point / end point calculation means to the position of the end point based on the longitudinal cross-section focus degree distribution corresponding to each position at positions separated by a predetermined interval within the range of one wire. By tracking a location with a high degree of focus, the trajectory from one connection surface to which one end of one wire is connected to the other connection surface to which the other end of the wire is connected is tracked. And a tracking means for detecting the bonding wire. The bonding wire detection device according to claim 1, further comprising: a tracking image creating unit that creates a tracking image in which a plurality of the longitudinal cross-section focus degree distributions are continuous . 3. The tracking unit according to claim 1, further comprising: a virtual tracking unit configured to virtually track when a portion with a high degree of focusing in the middle of tracking does not exist in the longitudinal section focusing degree distribution. The bonding wire detection apparatus as described. A bonding wire detection method for three-dimensionally detecting a wire bonded to a connection surface,
Take multiple images of wires with different focal points, relatively close to and away from the bonded wires,
In the acquired image, identify the region of one connection surface to which one end of the wire is connected and the region of the other connection surface to which the other end of the wire is connected,
Based on the positions of the two areas of the identified connection surfaces, calculate the positions of the tracking start point and end point,
From the focus degree three-dimensional distribution in which the imaging surface focus degree distribution representing the focus degree distribution indicating the pixel position having a high focus degree for each acquired image with different focus is stored, the approach and separation directions And forming a vertical cross-section focus degree distribution in which the focus degree distribution is cut out on a vertical cross section that is a cross section in a direction perpendicular to the straight line connecting the two connection surfaces,
In a position separated by a predetermined interval within the range of one wire, a high-focus point is tracked from the calculated tracking start point to the end point position based on the longitudinal cross-section focus degree distribution corresponding to each position. By doing so, a trajectory from one connection surface to which one end of one wire is connected to the other connection surface to which the other end of the wire is connected is tracked. Detection method. The method for detecting a bonding wire according to claim 4 , wherein a tracking image in which a plurality of longitudinal section focusing degree distributions are made is created . 6. The method of detecting a bonding wire according to claim 4, wherein virtual tracking is performed when there is no portion with high focusing degree in the middle of tracking in the focusing degree distribution in the longitudinal section .

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