Appearance inspection system for electronic component

Abstract

Provided is an appearance inspection system capable of accurately detecting breakoff of a terminal electrode (W1) of an electronic component.　This appearance inspection system comprises: an inspection unit (100) provided with an illumination means that illuminates an inspection object (W), a conveyance means (1) that conveys the inspection object, and an imaging means (2); an inspection control unit (200) provided with an image acquisition unit (31) that uses, as an inspection image, an image signal from the inspection object acquired by the imaging means, an image processing unit (32) that performs image processing on the inspection image, a determination unit (34) that determines the inspection image, and a system control unit (35) that controls the illumination means, the conveyance means, and the imaging means; and a communication means (4) that connects the inspection unit and the inspection control unit. The illumination means is composed of an upper surface illumination device (10) and a lower surface illumination device (20) which are disposed above and below the conveyance means, respectively, so as to face each other. The upper surface illumination device is provided with an opening (15) for capturing an image of the inspection object. Each of the upper surface illumination device and the lower surface illumination device is provided with a first light source group which is disposed in a manner orthogonal to the conveyance direction of the conveyance means, a second light source group which is disposed in a manner oblique to the conveyance direction of the conveyance means, and a third light source group which is disposed in a manner horizontal to the conveyance direction of the conveyance means. The light source arrangements of the first light source group and the second light source group are in a mode in which red-colored light sources and blue-colored light sources are arranged in a staggered manner. The light source arrangement of the third light source group is in a mode in which only green-colored light sources are arranged. The imaging means is disposed such that an imaging optical axis (X) is at an elevation angle (θ) of 5-60° with respect to the conveyance direction (A) of the conveyance means at an inspection position (P) on the conveyance means.

Description

Visual inspection system for electronic components

[0001] The present invention relates to an appearance inspection system that can accurately inspect the appearance, particularly the end faces, of hexahedral electronic components such as chip capacitors and chip light-emitting diodes.

[0002] Chips and peeling that form on the terminal electrodes of hexahedral electronic components such as chip capacitors affect product quality as defects in the terminal electrodes, thus creating a need for inspection equipment that can accurately inspect defects present on the terminal electrodes. When inspecting the end faces of hexahedral electronic components such as chip capacitors, the electronic component is transported in a predetermined transport direction by a transport means, and at an inspection position set at a predetermined location during transport, the end face of the electronic component is illuminated by an illumination means, and the end face of the electronic component is imaged from the oblique front by an imaging means. On the other hand, in recent years, electronic components have become smaller, and in order to respond to this miniaturization, it is necessary to appropriately arrange the imaging camera and illumination device in order to accurately image the end face characteristics.

[0003] Patent documents 1 to 3 disclose an inspection device that includes an illumination mechanism for illuminating the inspection surface of an object to be inspected (electronic component) at a predetermined inspection position on a transport path. This illumination mechanism is configured such that a light emitter closer to the transport path is positioned further away from the inspection position than another group of light emitters, creating a space between the light emitter closest to the transport path and the other group of light emitters for imaging the inspection surface of the object to be inspected. The imaging camera is positioned so that the angle (elevation angle) between the transport direction and the imaging optical axis of the imaging camera is as small as possible. However, patent documents 1 to 3 disclose determining terminal electrode peeling of an electronic component by a decrease in the amount of reflected light, and do not disclose selectively determining terminal electrode peeling of an electronic component by selecting the wavelength of illumination light. Patent documents 4 and 5 disclose an inspection device that includes an illumination mechanism for illuminating the inspection surface of an object to be inspected (electronic component) at a predetermined inspection position on a transport path, the illumination mechanism comprising a blue illumination means for emitting blue light and a red illumination means for emitting red light, and an image acquisition unit consisting of a color image acquisition unit for acquiring a color image of the object to be inspected illuminated by the two different colored illumination means, and the blue illumination means and red illumination means are arranged so that the inspection light from the blue illumination means illuminates the external surface of the object to be inspected and the inspection light from the red illumination means penetrates the interior of the object to be inspected. However, patent documents 4 and 5 do not disclose a method for selectively determining terminal electrode peeling of an electronic component by mixing blue and red illumination light.

[0004] Japanese Patent Publication No. 2014-160016, Japanese Patent Publication No. 2020-115110, Japanese Patent Publication No. 2021-156808, Japanese Patent Publication No. 2007-64801, Japanese Patent Publication No. 2009-36710

[0005] The present invention relates to the internal electrode W illustrated in Figure 1. ２ Terminal electrode W at the end １ Defects in a chip-type capacitor (hexahedral electronic component, hereinafter referred to as "object under inspection W"), particularly terminal electrodes W １ The objective is to provide a visual inspection system that can accurately detect peeling.

[0006] The problem of the present invention can be solved by the following embodiments (1) to (6). Specifically,

[0007] (Aspect 1) An appearance inspection system comprising: an inspection unit equipped with illumination means for illuminating an object to be inspected, transport means for transporting the object to be inspected, and imaging means; an image acquisition unit that uses an image signal from the object to be inspected acquired by the imaging means as an inspection image; an image processing unit that processes the inspection image created by the image acquisition unit; a determination unit that determines the inspection image processed by the image processing unit; an inspection control unit equipped with a system control unit that controls the illumination means, the transport means, and the imaging means; and a communication means that connects the inspection unit and the inspection control unit, wherein the illumination means is arranged opposite to the transport means above and below The system comprises a surface illumination device and a bottom illumination device, the top illumination device having an opening for imaging the object to be inspected, and both the top illumination device and the bottom illumination device each comprising a first light source group arranged perpendicular to the transport direction of the transport means, a second light source group arranged inclined with respect to the transport direction of the transport means, and a third light source group arranged horizontally with respect to the transport direction of the transport means, and the imaging means having its imaging optical axis X positioned at a predetermined elevation angle (θ) with respect to the transport direction of the transport means at the inspection position P on the transport means. By employing polygonal (for example, hexagonal) dome illumination, it is possible to have a first light source group arranged perpendicular to the transport direction, a second light source group arranged inclined with respect to the transport direction of the transport means, and a third light source group arranged horizontally with respect to the transport direction of the transport means, so that uniform direct illumination light can be irradiated to the front and back surfaces, oblique sides, and end faces of the object to be inspected, so that peeling and defects in the object to be inspected can be detected with high accuracy.

[0008] (Aspect 2) The appearance inspection system described in Aspect 1 is characterized in that the light source arrangement of the first and second light source groups is a staggered arrangement of red and blue light sources, and the light source arrangement of the third light source group is a staggered arrangement of green light sources. This is because the first and second light source groups, which serve as end-face illumination to illuminate the sides and end faces of the object to be inspected, are arranged with a staggered arrangement of red and blue illumination, and by irradiating the object to be inspected with red and blue illumination from the same direction, the exposure of copper-colored (red-colored metal) internal electrodes due to peeling of silver-colored (blue-colored metal) terminal electrodes can be accurately detected during end-face inspection of the object to be inspected.

[0009] (Aspect 3) An appearance inspection system according to either Aspect 1 or Aspect 2, characterized in that the elevation angle (θ) is 5 to 60°. By setting the elevation angle (θ) to 5 to 60°, more preferably 15 to 45°, the terminal electrode W １ This is because it can accurately detect peeling.

[0010] According to the present invention, a polygonal (e.g., hexagonal) dome illumination system is employed that can illuminate the front, back, oblique sides, and end faces of the object to be inspected. Furthermore, a substrate-mounted high-brightness LED with a wide beam angle while maintaining high brightness is used as the illumination light source for the dome illumination system. This allows for uniform illumination of the front, back, sides, and end faces of the object to be inspected, enabling accurate detection of peeling and defects in the object. The first and second light source groups, which provide end-face illumination for the sides and end faces of the object to be inspected, are arranged in a staggered pattern of red and blue illumination. By irradiating the object to be inspected with red and blue illumination from the same direction, the exposure of copper-colored (red-colored metal) internal electrodes due to peeling of silver-colored (blue-colored metal) terminal electrodes can be accurately detected during end-face inspection of the object to be inspected. Additionally, by using green illumination for the third light source group that illuminates the front and back surfaces of the object to be inspected, shape defects in the object can be accurately detected without interference from the red and blue illumination.

[0011] This is an illustrative diagram of a hexahedral electronic component that is the object to be inspected by the visual inspection system of the present invention. This is a configuration diagram illustrating the configuration of the visual inspection system of the present invention. This is a side view showing an embodiment of the inspection unit constituting the visual inspection system of the present invention. This is a front view showing an embodiment of the inspection unit constituting the visual inspection system of the present invention. This is a light source arrangement diagram of the lighting device constituting the lighting means of the visual inspection system of the present invention. This is an explanatory diagram of the mechanism for determining terminal peeling by the visual inspection system of the present invention.

[0012] A description of an embodiment for carrying out the present invention will be given with reference to Figures 1 to 6. However, Figures 1 to 6 are just examples of embodiments and are not limited thereto.

[0013] 1. Diagram 2 of the visual inspection system configuration is an illustrative diagram of the configuration of the visual inspection system 300 of the present invention. The object to be inspected W is placed on a rotating means 3 on a transport means 1 and transported in the transport direction A, and an inspection image is acquired by an imaging means 2 at the inspection position P. The visual inspection system 300 of the present invention consists of an inspection unit 100, an inspection control unit 200, and a communication means 4 connecting the inspection unit 100 and the inspection control unit 200.

[0014] The inspection unit 100 includes illumination means (10, 20) for illuminating the object to be inspected W, a transport means 1 for transporting the object to be inspected W, a rotating means 3 for rotating the object to be inspected W on a rotating axis, and an imaging means 2 positioned at an inspection position P on the transport means 1 with the imaging optical axis X at a predetermined elevation angle (θ) with respect to the transport direction A of the transport means. The imaging means 2 images the object to be inspected W through an opening 15 provided in the upper illumination device 10. The illumination means (10, 20) consists of an upper illumination device 10 and a lower illumination device 20 arranged opposite each other above and below the transport means 1. The upper illumination device 10 has an opening 15 for imaging the object to be inspected W. Furthermore, the upper lighting device 10 and the lower lighting device 20 each include a first light source group 11 arranged perpendicular to the transport direction A of the transport means 1, a second light source group 12 arranged inclined with respect to the transport direction A of the transport means 1, and a third light source group 13 arranged horizontally with respect to the transport direction A of the transport means 1.

[0015] The inspection control unit 200 includes an image acquisition unit 31 that uses the image signal from the object to be inspected W acquired by the imaging means 2 as an inspection image, an image processing unit 32 that processes the inspection image acquired by the image acquisition unit 31, an information storage unit 33 that stores a processing program for executing the image processing and information necessary when the program is executed, a determination unit 34 that makes a determination on the inspection image processed by the image processing unit 32, and a system control unit 35 that controls the transport means 1, the imaging means 2, and the illumination means (10, 20).

[0016] The following will describe the inspection target object W, the inspection unit 100, the inspection control unit 200, and the communication means 4 in that order.

[0017] 2. The object to be inspected by the visual inspection system 300 of the present invention is not particularly limited as long as it is a hexahedron that requires end-face inspection. Specifically, it is an electronic component such as a chip capacitor or a chip light-emitting diode. This is because chips and peeling formed on the electrode portion of the end face affect product quality as defects in the electrode portion, and therefore there is a need for an inspection device that can accurately inspect defects present on the electrode portion of the end face of an electronic component.

[0018] 3. Inspection Unit Figure 3 is a side view showing an embodiment of the inspection unit 100, which includes a transport means 1 for transporting an object to be inspected W, and Figure 4 is a front view showing the embodiment. The inspection unit 100 constituting the appearance inspection system 300 of the present invention includes illumination means (10, 20) for illuminating an object to be inspected W, a transport means 1 for transporting an object to be inspected W, a rotating means 3 for rotating the object to be inspected W on a rotating axis, and an imaging means 2 positioned at an inspection position P on the transport means 1 with the imaging optical axis X at a predetermined elevation angle (θ) with respect to the transport direction A of the transport means.

[0019] (3-1) Illumination means The illumination means of the appearance inspection system 300 of the present invention consists of an upper illumination device 10 and a lower illumination device 20 that are arranged opposite to the upper and lower sides of the transport means 1. Both the upper illumination device 10 and the lower illumination device 20 include a first light source group (11, 21) arranged perpendicular to the transport direction A of the transport means 1, a second light source group (12, 22) arranged inclined with respect to the transport direction A of the transport means 1, and a third light source group (13, 23) arranged horizontally with respect to the transport direction A of the transport means 1. The first light source group (11, 21), the second light source group (12, 22), and the third light source group (13, 23) are fixed to light source support parts (16, 26), respectively. The shape of the light source support section (16, 26) is polygonal (a hexagon when the upper and lower illumination devices are combined), and the light emitted from the first light source group (11, 21), the second light source group (12, 22), and the third light source group (13, 23) illuminates the end face of the object to be inspected W, the slope between the end face and the upper (lower) surface, and the illumination light perpendicular to the upper (lower) surface, respectively. This allows for uniform illumination of the end face, slope, and upper (lower) surface of the object to be inspected W, enabling accurate detection of peeling and defects in the object to be inspected W. The upper illumination device 10 is equipped with an opening 15 for the imaging means 2 to acquire reflected light from the object to be inspected W.

[0020] (3-2) Light source arrangement diagram 5 is a diagram of the light source arrangement of the lighting device constituting the lighting means (10, 20) of the inspection unit 100 that constitutes the appearance inspection system 300 of the present invention, and is (a) a side view and (b) a perspective view, respectively. The lighting device consists of a first light source group (11, 21) arranged perpendicular to the transport direction A of the transport means 1, a second light source group (12, 22) arranged inclined with respect to the transport direction A of the transport means 1, and a third light source group (13, 23) arranged horizontally with respect to the transport direction A of the transport means 1. The first light source group (11, 21), the second light source group (12, 22), and the third light source group (13, 23) all consist of a plurality of LED light sources arranged at intervals of 1 to 10 mm in the X and Y directions. The LED light sources can be bullet-shaped or surface-mount type, but high-brightness surface-mount LEDs with a wide beam angle are preferred. The LED light sources are dimmable. For example, when metallic colors with different reflectivity are mixed together, the inspection can be performed more precisely by adjusting the amount of emitted light.

[0021] The first light source group (11, 21) and the second light source group (12, 22) constituting the illumination means (10, 20) of the inspection unit 100 of the visual inspection system 300 of the present invention are arranged in a staggered configuration of a red light source (wavelength range of 610 nm to 780 nm) and a blue light source (wavelength range of 460 nm to 500 nm). Terminal electrodes W of the object to be inspected １ By using a mixed color system with a staggered arrangement of red and blue light sources in the first and second light source groups that irradiate the object W, the red and blue light sources can be irradiated onto the object W from the same direction, and the terminal electrodes W of the object W can be irradiated. １ This is because, in the inspection, the exposure of the copper-colored (red-colored metal) internal electrode due to the peeling of the silver-colored (blue-colored metal) terminal electrode can be detected with high accuracy. On the other hand, the third light source group (13, 23) is configured to consist only of green light sources (wavelength range of 500 nm to 570 nm). By using only green light sources, it is possible to accurately detect shape defects in the object being inspected without interference from the red and blue illumination light.

[0022] Figure 6 shows the terminal electrodes W of a chip-type capacitor when using the visual inspection system 300 of the present invention. １It is an explanatory diagram for explaining a mechanism that can accurately determine peeling. Respectively, (a) is a good product, (b) the terminal electrode W １ Due to peeling, the internal electrode W ２ (Copper: red metal) is exposed defective product, (c) the terminal electrode W １ Only scratches due to deformation of (silver: blue metal), the internal electrode W ２ (Copper: red metal) is an example of a good product that is not exposed. And, (a) good product (b) defective product (c) the terminal electrode W of the good product １ The acquired images (R image, B image) irradiated by the illumination means (10, 20) in which the first light source group and the second light source group adopting the external inspection system 300 of the present invention are arranged in a staggered pattern with a red light source (Red) and a blue light source (Blue) are compared with the white illumination image (prior art). In the case of peeling of the terminal electrode W １ of the chip-type capacitor, since the terminal electrode W １ is (silver: blue metal), when peeling of the terminal electrode W １ occurs, the internal electrode W ２ (Copper: red metal) is exposed. Therefore, by irradiating the terminal electrode W １ with mixed illumination of a red light source (Red) and a blue light source (Blue) on the same irradiation axis and acquiring images from the red light source (Red) and the blue light source (Blue) by the imaging means 2, it is possible to selectively detect only those in which peeling of the terminal electrode W １ has occurred as defective, and those in which plating peeling of the terminal electrode W １ has not occurred can be regarded as good products.

[0023] (3-3) Imaging means The imaging means 2 of the visual inspection system 300 of the present invention is an image sensor using an integrated circuit (IC) that converts reflected light from the object to be inspected W at the inspection position P through the opening 15 into an image signal. Specifically, a plurality of photodiodes arranged on a planar silicon substrate is used, and an integrated circuit such as a charge-coupled device (CCD) or complementary metal oxide semiconductor (CMOS) is used for transfer. It is also composed of an optical system that forms an image of the object to be inspected W on the imaging surface of the solid-state image sensor, and a signal processing circuit that processes the output of the solid-state image sensor to obtain a brightness value for each pixel. A color area camera is preferred depending on the nature of the object to be inspected W. Also, at the inspection position P, the elevation angle (θ) of the transport means of the transport means with respect to the transport path of the imaging optical axis X is in the range of 5 to 60°, more preferably 15 to 45°.

[0024] (3-4) Conveying means The conveying means 1 of the visual inspection system 300 of the present invention comprises a disc-shaped rotating means 3 made of a transparent or translucent glass plate, and a drive mechanism (not shown) that rotates the rotating means 3 horizontally in the direction of arrow A, and the terminal electrodes W of the object to be inspected W at the inspection position P １ The rotation means 3 is controlled by the system control unit 35 so that it faces the imaging optical axis X of the imaging means 2.

[0025] 4. Inspection Control Unit The inspection control unit 200 of the visual inspection system 300 of the present invention is responsible for controlling the entire visual inspection system 300 of the present invention. Specifically, it includes an image acquisition unit 31 that acquires video signals from the imaging means 2 as images, an image processing unit 32 that processes the images acquired by the image acquisition unit 31 into inspection images, an information storage unit 33 that stores processing programs for executing image processing and information necessary when executing the programs, and a terminal electrode W of the object to be inspected W from the image-processed inspection image. １The system includes a determination unit 34 that determines whether there is peeling or damage, and a system control unit 35 that controls the illumination means (10, 20), the imaging means 2, the transport means 1, and the rotating means 3. System control information is input from the input device 36, and the operating status of the visual inspection system 300 and the inspection results are output from the display device 37.

[0026] (4-1) Image acquisition unit The image acquisition unit 31 is an imaging means 2 that captures the terminal electrodes W of the object to be inspected W. １ It is responsible for acquiring video signals from the unit as images and transmitting them to the image processing unit 32. It also has the function of controlling the operation of the imaging means 2, such as the timing of imaging, via general-purpose communication interfaces such as Camera Link, USB (Universal Serial Bus), CXP (CoaXPress®), and Gigabit Ethernet (GigE).

[0027] (4-2) Image Processing Unit The image processing unit 32 is responsible for performing various image processing operations on the image information from the image acquisition unit 31 to create an inspection image.

[0028] (4-3) Information Storage Unit The information storage unit 33 includes ROM (Read Only Memory) and RAM (Random Access Memory). The ROM stores various programs such as inspection method programs executed by the CPU, and information necessary for the execution of these programs. The various programs and information stored in the ROM are loaded into the RAM and executed.

[0029] (4-4) Determination Unit The determination unit 34 determines the terminal electrode W of the object to be inspected W. １ It plays a role in determining whether there is any peeling or damage.

[0030] (4-5) System Control Unit The system control unit 35 is responsible for controlling the lighting means (10, 20), the imaging means 2, the transport means 1, and the rotating means 3.

[0031] 5. Communication means The communication means 4 of the present invention has the role of transmitting the image signal acquired by the inspection unit 100 to the image acquisition unit 31, and the role of transmitting information that the system control unit 35 uses to control the illumination means (10, 20), the imaging means 2, the transport means 1, and the rotating means 3 to the inspection unit 100.

[0032] According to the present invention, end face inspection of a hexahedral electronic component can be provided.

[0033] 100 Inspection unit 200 Inspection control unit 300 Appearance inspection system W Inspection object, chip-type capacitor W １ Terminal electrode W ２ Internal electrode 1 Conveying means 2 Imaging means 3 Rotating means 4 Communication means 10 Upper surface illumination device 11, 21 First light source group 12, 22 Second light source group 13, 23 Third light source group 14, 24 Terminal 15 Opening 16, 26 Light source support part 20 Lower surface illumination device 31 Image acquisition part 32 Image processing part 33 Information storage part 34 Judgment part 35 System control part 36 Input device 37 Display device

Claims

1. An appearance inspection system comprising: an inspection unit equipped with illumination means for illuminating an object to be inspected, transport means for transporting the object to be inspected, and imaging means; an image acquisition unit that uses an image signal from the object to be inspected acquired by the imaging means as an inspection image; an image processing unit that processes the inspection image acquired by the image acquisition unit; a determination unit that determines the inspection image processed by the image processing unit; an inspection control unit equipped with a system control unit that controls the illumination means, the transport means, and the imaging means; and a communication means that connects the inspection unit and the inspection control unit, wherein the illumination means consists of an upper illumination device and a lower illumination device arranged opposite to the upper and lower surfaces of the transport means, the upper illumination device has an opening for imaging the object to be inspected, and both the upper illumination device and the lower illumination device are equipped with a first light source group arranged perpendicular to the transport direction of the transport means, a second light source group arranged inclined with respect to the transport direction of the transport means, and a third light source group arranged horizontally with respect to the transport direction of the transport means, The visual inspection system is characterized in that the imaging means is positioned at an inspection position P on the transport means with the imaging optical axis X at a predetermined elevation angle (θ) with respect to the transport direction of the transport means.

2. The appearance inspection system according to claim 1, characterized in that the light source arrangement of the first light source group and the second light source group is a staggered arrangement of red and blue light sources, and the light source arrangement of the third light source group is an arrangement of only green light sources.

3. The visual inspection system according to either claim 1 or 2, characterized in that the elevation angle (θ) is 5 to 60°.

Images