TW545089B - Automatic filter changer for use on surface mounter inspection camera - Google Patents

Abstract

A printed circuit board assembly machine inspects circuit boards and parts to be mounted on those circuit boards prior to assembly. This assembly machine may visualize and recognize physical features of the circuit boards and parts as part of this inspection. A filter may be deployed while visualizing certain types of circuit boards or parts to remove characteristic defects found in images of those types of parts. When several types of circuit boards or parts inspected by the assembly machine exhibit different characteristic visualization problems, the assembly machine may deploy a different filter for each type of circuit board or part.

Description

545089 A7 B7 V. Description of the Invention (1) This application is a continuation of the application in which the US Application No. 09 / 970,960 (listed on October 4, 2001) is the same as the one currently in the application. The present invention relates to the visualization of printed circuit boards and parts that present a problem of feature development. The present invention particularly (but not exclusively) has one type of physical special soil for identifying several types of printed circuit boards and electronic parts by computer vision, in which each type of circuit board and part contains different characteristic imaging problems. Automatic printed circuit board assembly equipment, such as the automatic component placement machine from Assembl0on, uses a computer vision system to inspect and accurately place printed circuit boards and the parts to be placed on such circuit boards. For the inspection of these objects, it is mostly necessary to visualize an object, identify the physical characteristics of the object, and analyze the physical characteristics of the physical characteristics. A blank printed circuit board or card is typically detected from a storage location, while computer vision equipment, which includes a camera and front lighting, is used by the combined machine to check the physical characteristics on the circuit board. Some of these physical features are called fiducials and are intended to precisely align the parts to be mounted on the board. These other physical features on the circuit board are solder contact pads. If the circuit board being inspected is not rejected, the combination machine places it in a position to receive the placement part. The parts to be placed were then detected from the storage location, and the computer vision equipment, again, including the camera and front lighting, was used by the combination machine to inspect the parts. If the part has not been rejected, the combined machine will manipulate the part to position it correctly to align its mounting position on the circuit board or card. However, when computer vision systems try to inspect a certain type of circuit board or component, characteristic problems can occur. Some boards or cards are made of a light-colored ceramic material. -4- This paper size applies to China National Standard (CNS) A4 (210X 297 mm).

Hold

Line V. Description of the invention (2 materials produced and have gold or silver benchmarks do not provide the current computer vision ~ ... know the contact point. These colors are "back to the visual system to fully identify the reference point or contact point. V 'pieces that make a reliable, silver, or silver metal contact with a metal contact point on a white or light-colored ceramic backing will encounter discrimination ^ relying on recognition. It will be hindered by similar questions. The lack of one-color background for this contact point allows the reliable identification of contact with other parts, with one color in the other two colors when the image is compared with a monochrome camera, and the points are fully contrasted. A sip of mouth w 符 and J 符 符 符 敛 是 is a glare from the contact point and the background, and it also prevents the reliable identification of the contact point. Then another question 4 will occur, because the package typically used in computer vision Charge-coupled device (CCD) cameras are extremely sensitive to infrared rays. As a result, parts of the image of the part that are specifically reflected in the infrared spectrum are diluted and difficult to identify reliably. The forerunner of this application, Teach a new technology for identifying parts with metallic contacts on a light background. However, a printed circuit board assembly machine 'must often process a mixture of circuit boards and parts, each of which presents a different One or more of the above identification problems. At present, there is no technology that can be used in a printed circuit board assembly machine to overcome the various identification problems it encounters. A printed circuit board assembly that handles several different types of circuit boards and parts in one Various aspects of the present invention can be found in a machine and method. In this method and device, when a certain type of circuit board and parts are inspected, the description of the invention (3 will be automatically allocated and used. ，， 卢 &amp; ， "㈣" When visualizing the -type object, it will correct the characteristic problems encountered., Between a silver reference point and a light-colored print, and between light-colored parts with = board <between , Or the contrast in the silver image of the point of contact 'can be used to polarize the circuit board, Zhao Mingcheng, and Quan, and make the board or zero ,,, and the line of the moon, a — Improving the linear polarized light filter of the polarizing gimbal of the illumination filter, and improving it. In the image of a part, between one side, Beidan, and Wan, the contact point of the color is the same as that of the other color. The contrast between them can be improved. The straw parts are imaged through a color filter, and the glare added to a circuit board or part can be imaged by the plate scale through a circular polarization filter. The effect of the infrared radiation reflected on the -CCD camera can be improved by imaging the plate or τ component, two or one infrared-repellent filter, and improving the image of the plate or component. More specifically, "An aspect of the present invention can be found in the following method for visualizing an object with physical characteristics on the background. The object is:-an illumination source illuminates an image with electromagnetic radiation from the object The 40% of the reflected% z light shot has a characteristic blemishes related to the type of the visualized object. The reflected electromagnetic radiation is automatically filtered to remove the characteristic flaws from the image, thereby improving the contrast between the physical features and the background in the filtered image. The physical characteristics of the circuit board or part can be identified in the filtered image for inspection purposes'. Another aspect of the present invention can be used for visualizing a background with -6-545089.

Examples of physical features &amp; η &gt; ^ found in a spoon device. One or more light sources illuminate the object with electromagnetic radiation. An imaging device takes an image of electromagnetic radiation reflected from the object. The 'side image' has a characteristic defect. Shaw is driven by the type of the visual object to position a filter in one place, so that the image 〉 The filter's% magnetic radiation is used to remove the feature defects from the image and improve the contrast between the physical characteristics and the background in the image. In a modified embodiment of the present invention, the filter is pushed straight into the position. In another exemplary embodiment of the present invention, a plurality of usable filters are placed on the roulette and are rotated into position. Another aspect of the present invention can be found on a circuit board or card on which there is a surface-mounted part that has been identified according to the method. Through the use of 3 methods, align the physical characteristics of the installed parts with the contact points of the board or card. In other aspects of the present invention, the following detailed description is read in conjunction with the accompanying drawings: 'Don't become obvious; in the attached drawings: Figure 1 is a schematic front cross-section of a visualization, identification and placement device according to the present invention. View; FIG. 2 is a top view of the lighting and receiving portion of FIG. 1 when viewed from line 2_2; FIG. 3 is a cross-sectional view of the device for visualization, identification, placement, and linear filter assembly according to the present invention, When the filter is evacuated; FIG. 4 is a cross-sectional view of the filter in use; FIG. 5 is a cross-sectional view of another specific embodiment of the present invention, showing a rotary filter assembly device; and

Binding

545089 A7 ------- -B7 V. Description of the invention (1) -------- ~ One Fig. 6 is a top view of one of the rotating filter fitting device of Fig. 5. • As shown in FIG. 1 of the drawings, a specific embodiment of the present invention is used to visualize a weak contrast background with metal objects against a dielectric or non-metallic background &lt; parts, which is associated with traditional computer vision The system 10 explains it; the 7-brain vision is recognizable—often a two-spoon ball-straw array (BGA) 12 of the small highly fused solder beads 14; the solder beads 14 are carried by a ceramic dielectric substrate 16. The GA 12 is held by a gripper of a pick-up machine (not shown) or a manipulator 8 above an upper-view camera 20 of a computer vision system 10. The camera 20 captures an electronic image and provides the image to a computer vision system, which uses the electronic image to identify and inspect the 3012 solder beads 14 in relation to the body, size, and space. If the BGA 12 passes the inspection, the vision system 10 uses the robot 18 to align the contact points 24 of the circuit board or card 22 with the identified BGA solder beads 14 on a circuit board or card 22 to manipulate the displacement of the bag 12 And set. As in the old practice, before the BGA 12 and other surface-mounted components are placed on the circuit board or card 22, the contact point 24 is coated with a eutectic flux, and the BGA is placed. 12 and other surface-mounted components on the circuit or card 22, heat the card and the set Bga and other components to melt the flux into the fillet (not shown), and securely The BGA surface is mounted on the circuit board or card. In the weakest contrast situation, when the welding beads 14 are silver and the substrate 16 is white or light-colored, a light box 26 is used in combination with a polarizing filter 28 in front of the camera 20 lens 30 to provide a BGA 12 —Polarization that is generally facing upwards and inwards -8- This paper size applies the Chinese National Standard (CNS) A4 specification (210 X 297 mm) 545089 A7 _______B7 V. Description of the invention (6 ~ Chemical lighting I '俾 will borrow a camera 20. Correctly visualize the welding beads 丨 4, and correctly identify the welding beads 14 by the vision system 10. As shown in FIG. 2, a specific embodiment of a preferred light box 26 has a central Aperture 32 'The camera 20 passes through the polarizing filter 28 and looks upwards through the aperture 32' The light box 26 also has four truncated cone-shaped upwardly and outwardly inclined trapezoidal surfaces 34, 36, 38, and 40, each The planes form a separate polarized light source. The four planes 34, 36, 38, and 40, including polarizing filters 42, 44, 46, and 48, are covered by individual, light-emitting diodes (LEDs). Opalescent glass diffuser screen 50 above array 52. The direction of linear polarization passing through polarizing filter 28 is taken as 0 °, The optical filters 42 and 44 are oriented to pass linearly polarized light in the direction of 90. The polarizing filters 48 and 46 are oriented to pass linearly polarized light in the direction of 180. The result is' the solder ball 14 The component of the downwardly-directed light reflected from the four light sources has a polarization of 90 °, which is, or is almost, orthogonal to the polarization direction through the polarizing diaphragm 28. So it is not reflected by the beads at all The incoming light reaches the lens 3 of the camera 20. On the other hand, the downward-directed component of the light reflected from the white or light-colored substrate 16 is approximately uniformly distributed in the polarization and has a considerable amount of light Reflected downward from the substrate 16 and passed through the polarizing filter 28 to reach the lens 30 of the camera 20. As a result, in the electronic image taken by the camera 20, the 'beads 14 generally appear very dark and the substrate 16 'Appears very white' and provides a good contrast for reliable identification of the bead 14. The effect of this comparison is thought to be due to the preservation of the polarization of electromagnetic radiation reflected from a dazzling metal object and the reflection from A dielectric The body's electromagnetic radiation-9-i Paper size National Standard (CNS) A4 size (21GX 297 public love) --- --- 545089 A7 B7 The invention illustrates the contrast of degraded polarization. A printed circuit board assembly The machine, in the process of assembling a single circuit board, will have to inspect different types of parts. If the part under inspection has a light-colored base and the other has a black-based base, another problem will occur. Because of linearity The efficiency of the polarizing filter 28 is that the welding beads η in the electronic image captured by the camera 20 are generally black and dark. When the welding beads are visualized through such filters, the welding beads have Black parts are not easy to identify. In this situation, when visualizing a part with a white substrate, it is necessary to equip the front of the lens 30 of the camera 20 with a cross-piece 28, and when visualizing a part with a black substrate, the filter is evacuated. A similar problem occurs when a printed circuit board assembly machine processes a printed circuit board or card. Some circuit boards are made of fiberglass substrate, and fiberglass is typically green in color. This base provides a good silver or gold reference point for parts being mounted on a circuit board, with good contrast. however

Other circuit boards or cards handled by the same combination machine will also have white or other light-colored ceramic substrates, which provide a poor comparison of this reference point. The technology described above, which is appropriately equipped with a filter to reliably identify the solder beads on parts with a light or dark base, can also be used on light or dark printed circuit boards and cards to reliably identify metal references. point. The control system of a circuit board assembly machine typically uses the specification files of various types of objects (printed circuit boards, cards or parts) it processes. This _ file contains information about the characteristics of various types of objects. Information obtained from the file: The number and position of the features (such as the reference point and contact point on the board and card, or the contact point on the part) are provided to the computer vision system in the inspection. Paper size suitable for GS home standard (CNS) A4 specification (21G x 297 public love) 545089 5. Description of the invention (8 used in the investigation process. In a combination machine known to use the technology of the invention, Tian Shila The file also refers to "Senior Citizen" "," Nowhere-the filter needs to be added, when to check the information of a certain type of object, and for the specific embodiment shown in Figure 5 What type of filter needs to be used? Now, as shown in FIG. 3, 'showing the first embodiment of the present invention, there is a Zubei embodiment, which uses a linear filter assembly device 60, and, , # Σ m and in the evacuation position. U61 is attached to the linear actuator by the link 64, and when the field W 3 road circuit board control system is powered, the linear actuator 65 will take the shown performance — from The optical axis of the camera 20 is evacuated. When power is removed by the control system: the linear actuator 65 Taken patterns shown in FIG. 4 - the connecting rod extending out of, the filter 61 is disposed in front of the camera lens 3〇 of 2〇.

For certain types of linear actuators, the motion of the actuator &amp; will be the opposite of that described above ... When the actuator 65 is powered, a minus piece will be used Η: When the actuator 65 loses power 'The cymbal 61 will be withdrawn. The previous description is in the discussion-using a linear actuator to distribute the use-the subtractor I should be aware of 'In a specific embodiment of the present invention, an electromagnetic coil may also be used. The cymbal 61 in FIGS. 3 and 4 may be the linearly polarized light filter 28 ′ shown in FIG. ^ Used in combination with-linearly polarized illumination, as described above, to correct the correlation—the display of the characteristics of the metal entity on a light background Like question. Alternatively, "M can be one of several other types 'selected to correct other characteristic problems', which will now be explained. These other types of cymbals can be used in equal benefit with polarized or non-polarized lighting. If Objects being visualized have, for example, the red entity features a green-11-this paper size applies to China National Standard (CNS) A4 specifications (210X297 public love) 545089 A7 ______B7 _ 5. Description of the invention (9) Color background In the above, the filter 61 can choose a red filter. Such a filter will allow the red light reflected from the red solid feature to pass, causing the solid feature to appear substantially white in the image obtained from the monochrome camera. The background is essentially black. If the camera 20 uses a charge-coupled element (CCD) to capture an electronic image, which is particularly reflective in the infrared spectrum, it may present a different characteristic imaging problem. Because CCD is a very Light shot sensitive to the infrared spectrum 'The electronic image of this object may be diluted, so that the physical characteristics and the blame of the 3 objects are in the image' The light gray object image prevents the computer vision system from recognizing the physical characteristics of the object. For this type of object, the filter 61 can use an infrared filter, which blocks infrared radiation and allows visible light to pass. Blocks infrared radiation The CCd will be made to use only the visible light reflected from the self-contained object to form an electronic image. In the filtered image, there is a better contrast between the physical characteristics of the object and the background. If you visualize some objects in Glare on the feature, the image produced by the camera 20 will also be diluted. In this situation, the filter 61 can be used as a circular polarized light filter. Such a filter can limit the reflection of the illumination from the object. Rotate the component to reduce glare from the object and correctly identify the physical characteristics on the object. Although in the previous discussion, the contact points on electronic parts or fiducial points, and on printed circuit boards and cards have been identified It is necessary to understand that the physical characteristics identified on other objects may not be touch points or reference points. For example, When a lens is mounted on a light-emitting Z-pole body, the reason why the lens can be attached to the circuit board or card is -12- The standard of this paper is applicable to China National Standard (CNS) Α4 specification (210X297 --- ------- 545089 A7 B7 V. Description of the invention The circuit board or card may be inspected for the characteristics of the heat-hardened equipment. Similarly ^ JCi Office L strict adhesive point of adhesive (which is used for (Both parts are mounted to the board by welding), and the orientation and orientation are checked.

If the objects processed by a circuit board assembly machine each present a different characteristic problem, then "depending on the inspected object," one of several different filters must be selected to reliably identify the object. Physical characteristics. A specific embodiment of the present invention which can dispense and use various filters is shown in FIG. 5 of the drawings. Shown is a rotary filter attachment device 70, which is a filter wheel 75 mounted on a rotating shaft of a step motor 76. It can also be seen in Figure 5 that the filters 61 and 63 are mounted on the filter wheel 75 and are aligned with the apertures "and". The step motor 76, in response to a signal from the control system of the combined machine, will rotate to a clearly designated position to use a cymbal adapted to the visualized part.

The rotary filter assembly device 70 is shown in more detail in FIG. 6. In this particular embodiment of the present invention, it can be seen that the filter wheel 7 5 has four apertures 71, 72, 73, and 74. The apertures 72, 73, and 74 are covered by the filters 61, 62, and 63, respectively, and the apertures 71 are not covered by the filters. The hub of the filter wheel 75 is attached to a rotating shaft of the step motor 76. The lens 30 is visible through the aperture 74. Although, as mentioned above, the motor 76 is a stepped motor. 'It should be understood' In a specific embodiment of the present invention, a servo motor can also be used. In response to a signal from the control system of the combined machine, the filter The sheet wheel 75 is positioned. Although Figures 3, 4, and 5 show a specific embodiment of the present invention, which is used to visualize BGA packaging, 'should be recognized, the technology of the present invention is available. • 13-This paper standard applies to the Household Standards (CNS) A4 specifications (X 297 public love) &quot; &quot; -S, 545089 A7 B7 5. Description of the invention (11) to improve the SL-style package with &amp; printed circuit board and card visualization. Although the specific embodiment discussed above 'only uses a single filter device,' it should be understood. 'In another specific embodiment of the present invention, multiple filter devices can be used to gather multiple types of cymbals together. Spare to improve the visualization of objects with many characteristic problems. It should now be recognized that the object of the present invention has been successfully achieved. Although the present invention has been described in detail, many modifications are possible within the spirit and scope of the present invention, and should be recognized. When attaching the scope of the patent application after the release, please understand ... -a) "Including (C0mprising)" does not exclude the existence of elements or steps listed in the terms of a patent application;… The article "— (a4an)" before the-element does not exclude the existence of multiple such elements;-0 in: "Any reference sign in the patent scope does not limit its scope-d) several" means ) "May represent the same hardware object or the same software execution structure or function ^ -14- This paper size applies the Chinese National Standard (CNS) A4 specification (210X297 public attack ·)

Claims (1)

545089 ι ·-A method for visualizing on the background-an object (12) with physical characteristics (14), used in an automatic printed circuit board assembly machine, the method includes the steps of: using an illumination light source (26) Illuminate the object with electromagnetic radiation, including the physical characteristics and the background; take an image of electromagnetic radiation reflected from the object, the image containing feature defects related to the object type; and automatically filter (60, 70) the The reflected electromagnetic radiation removes the characteristic flaws in the image, thereby reducing the characteristic flaws in the filtered image, and produces an improved contrast between the physical features and the background. 2. The method according to item 丨 of the patent application scope further includes the step of identifying the entity feature (14) in the image. 3. The method according to item 丨 of the patent application, wherein the electromagnetic radiation is light and the filtered image is captured by a camera. 4. The method according to item 2 of the scope of patent application, wherein the electromagnetic radiation is light and the filtered image is taken by a computer vision camera. 5. The method according to item 丨 of the scope of patent application, wherein the object is a printed circuit board. 6. The method according to item 2 of the scope of patent application, wherein the object is a printed circuit board. 7. The method according to item 1 of the scope of patent application, wherein the object is a part to be mounted on a printed circuit board. 8 · The method according to item 2 of the scope of patent application, in which the object is a stand-by. -15- This paper size applies Chinese National Standard (CNS) A4 specification (210X297 mm) 545089 A8 A component mounted on a printed circuit board. 9.—A kind of ancient and traditional object for visualizing the background on the background. It is used in an automatic printed circuit board assembly machine. The device is in a batch or batch mode. The device includes ... Several light sources (26) are used to illuminate the object with electrical% radiation; an imaging device (20) is used to capture-reflected electromagnetic reflection images of the object, the image contains the object and the object Characteristic features related to earth type;-filter (61); and-actuator (65, 76), the "set so that the shadow" is formed by electromagnetic projection through the diaphragm, so that the filter Reduces feature blemishes in # images and creates an improved contrast between physical features and background. ίο. The device according to item 9 of the patent application includes-computer vision system (10) for identifying the physical features in the filtered image. 11. The device according to item 9 of the scope of patent application, wherein the electromagnetic radiation is light and the imaging device is a camera. 12. The device according to item 10 of the scope of patent application, wherein the electromagnetic radiation is light and the imaging device is a camera of the computer vision system. 13. The device according to item 9 of the scope of patent application, wherein the object is a printed circuit board. The remote object is a printed product, and the object is a ready-to-install device. 14. The device circuit board according to item 10 of the scope of patent application. 15. Device according to item 9 of the scope of patent application A component mounted on a printed circuit board. -16- This paper size applies to China National Standard (CNS) A4 (210 X 297 mm) 545089 A8 B8 16. The device according to the scope of the patent application, wherein the object is a part to be mounted on a printed circuit board. Female 7. According to the device in the scope of Zhongli's patent, item 16 includes Xiao-manipulator, which uses the identified physical characteristics of the attack part to align the contact points of the circuit board or card, and positions the child part on a circuit board or card. . 18. —A circuit board or card with a surface-mounted component, which is identified by the method of item 8 of the scope of the patent application, and such surface placement is based on the component that has been identified. The physical characteristics are implemented on the contact points of the circuit board or card. -17- This paper size applies to China National Standard (CNS) A4 (210 X 297 mm)