JP5470708B2 - Illumination device and defect inspection apparatus using the same - Google Patents

Description

  The present invention uses an illuminating device for illuminating an area where the field of view of an imaging device is matched when an object having a predetermined shape is imaged for the purpose of observation, measurement, inspection, and the like, and this type of illuminating device. The present invention relates to a defect inspection apparatus.

  In the field of producing molded products with color coating or resin coating, the surface of the molded product has uneven defects such as scratches, blisters, hair dust, dirt defects due to cloudy paint and collection of fine scratches, paint, etc. It is inspected whether a color defect due to adhesion of the toner has occurred. Various inspection apparatuses for optically performing this type of inspection have also been developed.

  In the inspection of unevenness defects (hereinafter, including unevenness caused by dirt), generally, the inspection object (work) is illuminated using the high specular reflectivity of the molded product, and the illumination light A regular reflection light is imaged, and an area darker than the surroundings is detected as a defect on the generated image. On the other hand, in the inspection of color defects, diffuse reflected light from the workpiece is imaged, and areas darker or brighter than the surroundings are detected as color defects on the image. Determined by the color of the).

  The applicant has recently developed a defect inspection apparatus for the purpose of increasing the detection accuracy of defects detected using the specular reflectivity of a workpiece, such as an uneven defect (see Patent Documents 1 and 2).

JP 2007-240431 A JP 2007-240432 A

These documents disclose an inspection apparatus that includes two types of light sources that emit light of different colors and a color camera, and performs imaging by simultaneously turning on the light sources.
One light source (hereinafter referred to as “first light source”) emits light (coaxial illumination light) that travels along the optical axis of the camera, thereby illuminating the central portion of the region corresponding to the field of view of the camera. Is done. The other light source (hereinafter referred to as “second light source”) is a ring-shaped light source, and is arranged with its center aligned with the optical axis of the first light source and the camera. The illumination light from the second light source illuminates a region outside the illumination range by the first light source, and the specularly reflected light from the illumination range can be incident on the camera. Irradiate in a direction that is slightly inclined with respect to.

  Furthermore, in Patent Document 1, a third light source that irradiates light having a larger incident angle than the second light source is provided outside the second light source, and diffuse reflected light with respect to the light from the third light source is provided to the camera. It is described that a color defect is detected by guiding (see paragraphs 0082 to 0084, FIG. 10). Patent Document 2 describes that the accuracy of defect inspection is improved by overlapping the irradiation ranges of the first and second light sources (paragraphs 0029, 0052 to 0053, FIG. 1).

  As described in Patent Documents 1 and 2, the light from the first light source becomes light traveling along the optical axis of the camera by the half mirror. Although not explicitly disclosed in each document, the second light source is housed in a casing in which a cylindrical light passage portion is formed at the center, and a light diffusing agent is provided at the lower end portion of the light passage portion. A light emitting part is provided. The light emitting portion includes an inclined surface that is inclined so that the outer side is lower than the inner side, and the incident angle of light from the second light source is determined by the inclined angle of the inclined surface.

Hereinafter, a configuration including the first light source and the half mirror is referred to as a “first illumination unit”, and a configuration including the second light source, the light passing unit, and the light emitting unit is referred to as a “second illumination unit”.
FIG. 6 schematically illustrates imaging under illumination from each illumination unit. In the figure, reference numeral 10 denotes a camera lens, and reference numeral 12 denotes an optical axis of the camera. 2A is a first illumination unit, 2B is a second illumination unit, and W is a work to be illuminated.

  Moreover, about the 1st illumination part 2A, the light source and half mirror which are a component are shown with the codes | symbols 21 and 22, respectively. On the other hand, for the second illumination unit 2B, the illustration of the internal ring-shaped light source is omitted, and the central light passing unit and light emitting unit are denoted by reference numerals 200 and 201, respectively.

  Further, in FIG. 6, regular reflection regions (referred to as regions where specular reflection light having sufficient intensity can be incident on the camera lens 10 by the irradiated light) 101 and 102 generated on the surface of the workpiece W by each illumination light. Are shown by different patterns, and the optical path of the illumination light corresponding to the boundary between these regular reflection regions 101 and 102 is shown. The regular reflection region 101 is determined by the position of the upper opening of the light passage portion 200, the size of the opening, the position of the lens 10, and the like. The regular reflection region 102 is determined by the height, size, inclination of the light emitting unit 201, the position of the lens 10, and the like.

  The light from the first illumination unit 2 </ b> A is applied to the workpiece W through the light passage unit 200. In this example, the length of the light passage portion 200 is adjusted so that the regular reflection regions 101 and 102 are continuous.

  However, since the ring-shaped light source of the second illumination unit 2B is usually configured using a plurality of LEDs, if the distance from the ring-shaped light source to the light emitting unit 201 is short, the light from each LED is sufficiently diffused. Without being irradiated, the workpiece W is irradiated, and as a result, an image with uneven brightness may be generated. If luminance unevenness occurs, an error may occur in detection of a defect due to a difference in brightness, so that a sufficient distance between the ring-shaped light source and the light emitting unit 201 needs to be provided.

  In addition, it is desirable that the third light source for color defect detection described in Patent Document 1 is also incorporated in the second illumination unit 2B as a ring-shaped light source. However, as the number of LEDs increases, it becomes difficult to deal with a single substrate due to the configuration of the wiring circuit, the light source accommodation space, and the like, and a plurality of substrates must be arranged vertically.

  In order to make a suitable distance between the ring-shaped light source and the light emitting part 201 or to arrange a plurality of substrates vertically, as shown in FIG. 7, the height width of the second illumination part 2B is increased. There is a need. However, in this way, the light passage part 200 is inevitably long, and thereby the optical path of the first illumination part 2A is lengthened, and the range of the regular reflection region 101 of the first illumination part 2A is reduced. On the other hand, the height and inclination state of the light exit surface 201 of the second illumination unit 2B are the same as in the example of FIG. 6 and the relationship with the lens 10 is also maintained, so the range of the regular reflection region 102 is the example of FIG. As is the case, it becomes difficult to deliver light from the second illumination unit to the boundary position of the regular reflection region 101. As a result, a region 103 (hereinafter referred to as “non-specular reflection region”) in which regular reflected light with sufficient intensity cannot be guided to the camera is generated between the regular reflection regions 101 and 102 of the illumination units 2A and 2B. there is a possibility. When the surface of the workpiece W is a curved surface, the above phenomenon becomes more remarkable.

FIG. 8 is a schematic diagram showing the relationship between the regular reflection areas 101 and 102 in the area corresponding to the visual field of the camera. (1) in the figure shows an ideal relationship by the illumination shown in FIG. 6, and (2) shows an example in which the non-specular reflection region 103 is generated depending on the illumination state shown in FIG.
As shown in FIG. 8 (1), the regular reflection region 102 of the second illumination unit 2B continues around the regular reflection region 101 of the first illumination unit 2A, and a non-regular reflection region is generated between these regions. If there is no defect, the defect can be detected as an area darker than the surrounding area even if the defect is present anywhere in the illustrated range.

  On the other hand, as shown in FIG. 8B, when a dark non-specular reflection region 103 is generated between the two regular reflection regions 101 and 102, it becomes difficult to detect a defect in this region 103. Therefore, there is a limit to the range in which the height width of the second illumination unit 2B can be expanded.

  This invention pays attention to said problem, and provides the illuminating device of the structure which can prevent generation | occurrence | production of a non-specular reflection light area, ensuring sufficient distance between the ring-shaped light source of a 2nd illumination part, and a light-projection part. It is an object of the present invention to perform inspection with high accuracy by using the illumination device.

An illuminating device having a basic configuration for achieving the above object proceeds along the optical axis while diverging around the optical axis in the field of view of an imaging device arranged with the light receiving surface facing the object. A first illumination unit that irradiates light, and a first illumination unit that irradiates light that is disposed closer to the object than the first illumination unit between the imaging device and the object and travels in an oblique direction with respect to the optical axis of the imaging device. 2 illumination parts. The second illuminating unit guides the light emitted from the first illuminating unit to the object, and guides the reflected light from the object to the imaging device with respect to the light from each illuminating unit, and the light passage A ring-shaped light source arranged so as to surround the light source, and light having an inclined surface that is inclined so as to approach the object as it goes from the inside toward the outside, is linked to the edge of the light passing part on the side close to the object over the entire circumference. The area outside the range of illumination by the light that has exited the first illumination section and passed through the light passage section is illuminated by the light that has exited the ring-shaped light source and passed through the light exit section.

Furthermore, the light passing portion of the second illumination portion includes a first passage portion diameter farther from the first illuminating section together to have a receiving opening is conical small receiving divergent light from the first illumination unit, the first It is comprised by the short cylindrical 2nd passage part which connects 1 passage part and a light-projection part. The diverging light from the first illumination unit that has entered the first passage through the receiving port travels through the first passage and travels from the entire opening end surface of the second passage toward the first passage in the second passage. to go into. The ring-shaped light source is composed of a plurality of light emitters arranged along the outer peripheral surface in the vicinity of the receiving port of the first passage portion, and has a range from the position corresponding to the ring-shaped light source to the light emitting portion. A wall portion is provided to surround the outside of the ring-shaped light source. The light emitting portion is made of a material containing a light diffusing agent, and guides the light reaching the light emitting portion from the ring light source through the space between the light passing portion and the wall portion to the field of view of the imaging device while diffusing it. .

In the following, the upper and lower relationships are expressed with reference to the surface on which the object is illuminated . That is, the direction toward the surface to be illuminated and downward and a direction away the upper.

In the illuminating device described above, the light emitters constituting the ring-shaped light source are arranged along the outer peripheral surface in the vicinity of the receiving port of the upper first passage portion among the light passage portions of the second illumination portion, and the second lower portion is arranged . Since the light emitting part is integrally provided at the lower end part of the passing part, it is possible to secure a sufficient distance between the ring-shaped light emitting part and the light emitting part by adjusting the length of the first passing part. .

  When light from the first illumination part (hereinafter referred to as “first illumination light”) passes through the first passage part and reaches the opening end face of the upper end part of the second passage part, Since it becomes a corresponding magnitude | size and it progresses further below, this opening part can be considered as the output surface of 1st illumination light. In addition, since the length of the second passage portion can be shortened by providing the first passage portion, the specular reflection region by the first illumination light from the upper opening end surface of the second passage portion is widened, and the second passage portion is made. It can be made to be continuous with the regular reflection region by the light emitted from the light emitting part continuous to the lower end part of the passing part (hereinafter referred to as “second illumination light”).

In the first aspect of the illumination device, the second passage portion and the light emitting portion of the second illumination portion are integrally formed of a material containing a light diffusing agent, and the outer periphery of the first passage portion of the light passage portion. The inner peripheral surface of the surface and the wall is mirror-finished . According to this configuration, the second illumination light emitted from the ring-shaped light source is guided to the light emission part while being reflected by the outer peripheral surface of the first illumination part and the inner peripheral surface of the wall part, and further diffused by the light emission part. Since 2 illumination light can be propagated also to a 2nd passage part, the surrounding surface of a 2nd passage part can also be functioned as an output surface of 2nd illumination light. Therefore, the emission range of the first illumination light and the emission range of the second illumination light are close to each other at the upper end of the second passage part, and the difference in the irradiation angle of each illumination light is very small. The luminance near the boundary between the regular reflection areas of the illumination light can be increased, and the occurrence of non-specular reflection areas can be easily prevented.

In the second aspect of the illuminating device described above, the wall surface in the range from the position corresponding to the ring-shaped light source of the wall portion to a position that is a predetermined distance away from the light emitting portion side passes the first passage as it approaches the light emitting portion. It is formed in the inclined surface which inclines so that a part may be approached.

  According to said structure, the light emitted from the ring-shaped light source can be guide | induced to a light-projection surface, reflecting on the inclined surface of a wall part, or the outer peripheral surface of a 1st passage part. In addition, by inclining the upper portion of the wall portion, the light emitters constituting the ring-shaped light source can be arranged in a wider range than the range where the light is actually emitted from the light emitting portion, so the number of light emitters is increased, The light emission luminance can be increased by the reflection.

In the 3rd aspect of said illuminating device, it is based on the some light-emitting body which emits the light from which a wavelength range differs from the ring-shaped light source inside a 1st illumination part and a wall part outside the wall part of a 2nd illumination part. At least one second ring-shaped light source is disposed at a position closer to the light emitting unit than the ring-shaped light source inside the wall . Further, the inclined surface of the light emitting part continues to a position facing the outermost ring-shaped light emitting part.

  According to said structure, the 1st and 2nd passage part is used for the detection of a defect with high diffuse reflectivity, such as a color defect, using the space ensured by the light passage part of the structure which continued. It is possible to provide an illumination device provided with two ring-shaped light sources.

Further, according to the present invention, an image of the inspection object generated by the imaging device under illumination by the imaging device arranged with the light receiving surface facing the inspection object, the illumination device having the above-described configuration, and each illumination unit of the illumination device. processing the providing a defect inspection apparatus comprising a determining means for determining the presence or absence of irregular defect on the surface of the test object. According to this defect inspection apparatus, an image for inspection can be generated while performing illumination so that a non-specular reflection region does not occur, so that an uneven defect can be detected with high accuracy.

One embodiment of the defect inspection apparatus includes the illumination device according to the third aspect . The discrimination means processes an image of the inspection object generated by the imaging device under illumination by light from the first illumination unit and light from each ring light source of the second illumination unit, and the inspection object The presence or absence of irregularities and color defects on the surface of the film is determined. According to this defect inspection apparatus, both the unevenness defect and the color defect can be detected with high accuracy by one imaging, so that the added value of the inspection apparatus can be increased.

  According to the illuminating device having the above configuration, it is possible to ensure a sufficient distance between the ring-shaped light source and the light emitting unit, and the non-specular reflection region between the regular reflection regions by the light from the two illumination units. Can be prevented from occurring. Therefore, it is possible to generate a dark region in which it is difficult to detect a defect or an image having no luminance unevenness, and the defect can be detected with high accuracy within a wide range. In addition, it becomes easy to provide a second ring light source having a diameter larger than that of the light source below the ring light source in order to detect a color defect.

  Hereinafter, a resin molded product having a coated surface formed thereon (that constitutes the main body of a device such as a mobile phone) is referred to as “work W”, and whether or not irregularities or color defects have occurred in the work W is optically determined. A specific example of a defect inspection apparatus for inspecting automatically and a lighting apparatus used in the apparatus will be described in detail. In the following, for convenience, the surface of the workpiece W is assumed to be a plane along the horizontal direction, and the upper and lower relations are expressed with reference to this plane. However, the surface of the workpiece W is not limited to a horizontal plane, but is a plane along the vertical direction or oblique It may be a surface along the direction. Further, the surface of the workpiece W is not limited to a flat surface, and may be a curved surface having a predetermined curvature. In addition, the uneven defect may include unevenness due to dirt, and the color defect may also include color abnormality due to dirt in addition to the defect due to adhesion of paint.

FIG. 1 shows the configuration of the optical system of the inspection apparatus.
This optical system includes a camera 1 in which an imaging element 11 for color photography and a lens 10 are incorporated, and an illumination device 2. The camera 1 is arranged in such a manner that the light receiving surface faces the workpiece W side and the optical axis 12 is aligned with a direction corresponding to the normal line of the surface of the workpiece W (corresponding to a vertical direction in this figure).

The illumination device 2 includes a first illumination unit 2A that emits light along the optical axis 12 of the camera 1, and a second illumination unit 2B that emits light from a direction oblique to the optical axis 12 of the camera 1. Is provided.
Among these, the 1st illumination part 2A is comprised by the half mirror 22 arrange | positioned on the optical axis 12 of the camera 1, and the light source 21 (1st light source) arranged by the side.

  The 2nd illumination part 2B makes the main body the housing | casing 20 in which the circular opening part (not shown) was formed in the center part of the upper surface. A dome-shaped portion 24 is connected to the opening via a hollow body 23 whose top and bottom are open. The inner and outer peripheral surfaces of the hollow body 23 are formed in a mortar shape having a smaller diameter toward the lower end, and the outer peripheral surface is mirror-finished. A central portion connected to the hollow body 23 of the dome-shaped portion 24 is formed as a short cylindrical portion 25. Further, the entire dome-shaped portion 24 including the short cylinder portion 25 is integrally formed of a resin containing a diffusing agent.

  In the housing 20, three circular substrates 201, 202, and 203 each having a circular hole formed in the center are arranged vertically with a predetermined distance therebetween. The circular hole of the uppermost substrate 201 is formed to have a size corresponding to the outer diameter of the upper position of the hollow body 23. Hereinafter, the diameter of the circular hole increases as the substrate becomes lower. The hollow body 23 and the short cylinder portion 25 of the dome portion 24 are disposed in the circular holes of these substrates 201 to 203.

A plurality of chip-type LEDs 26 (hereinafter simply referred to as “LEDs 26”) are concentrically arranged and wired on the lower surfaces of the substrates 201 to 203 so as to surround the circular holes. The LED 26 of this embodiment is provided with light emitting elements corresponding to a plurality of colors.
The uppermost substrate 201 (hereinafter referred to as “upper substrate 201”) is provided in a state of being engaged with the upper portion of the hollow body 23 by the circular hole. A wall 27 is provided between the upper substrate 201 and the dome-shaped portion 24 so as to surround the arrangement range of the LEDs 26 of the upper substrate 201. The wall portion 27 has a configuration in which a mortar-shaped second wall portion 27b is integrated with the upper end of the cylindrical first wall portion 27a, and its inner surface is mirror-finished in the same manner as the outer peripheral surface of the hollow body 23. ing.

  A substrate 202 (hereinafter referred to as “middle substrate 202”) disposed at a position higher than the upper substrate 201 is disposed in a state of being engaged with the lower end portion of the second wall portion 27b by the circular hole. Further, a cylindrical wall portion 28 is provided between the middle stage substrate 202 and the dome-shaped portion 24 so as to surround the arrangement range of the LEDs 27 of the middle stage substrate 202. The lowermost substrate 203 (hereinafter referred to as “lower substrate 203”) is provided in a state of being engaged with the wall portion 28 by the circular hole.

  Further, each of the substrates 201 to 203 is screwed to the housing 20 at a plurality of locations on the peripheral edge in order to stabilize the position and posture. Screwing of each part is performed by bolt members 211, 212, 213 and a pair of upper and lower screw members 214, 215. At any location, the substrates 201, 202, 203 are connected by a series of connected bolt members 211, 212, 213 and a screw member 214, and the uppermost bolt member 211 is connected to the housing by the screw member 215. By fixing to the upper surface of 20, each substrate 201, 202, 203 is fixed at a predetermined height position. As a result, the substrates 201, 202, and 203 are respectively supported in a horizontal state, and the distance between the LED 26 and the dome-shaped portion 24 arranged on the substrate is almost constant in any substrate. The light irradiation intensity with respect to can be made uniform.

  The second illumination unit 2B having the above-described configuration is arranged in a state where the center of the hollow body 23 and the short tube portion 25 communicating with the hollow body 23 is aligned with the optical axis 12 of the camera 1. Thereby, the hollow body 23 and the short cylinder part 25 guide the illumination light (first illumination light) from the first illumination part 2A to the work W below, and from the work W with respect to the light from each illumination part 2A, 2B. Function as a light passage part for guiding the reflected light to the upper camera 1 (the hollow body 23 corresponds to the first passage part, and the short cylinder part 25 corresponds to the second passage part). In addition, each LED 26 on the upper substrate 201 forms a ring-shaped light source that surrounds the periphery of the hollow body 23 (first passage portion). Furthermore, a ring-shaped light source having a larger diameter (second ring-shaped light source) is formed by the LEDs 26 on the middle-stage substrate 202 and the lower-stage substrate 203.

  The dome-shaped portion 24 functions as a light emitting portion that emits light from each ring-shaped light source as light traveling obliquely with respect to the optical axis of the camera 1, and the inclined surface of the dome-shaped portion 24 faces outward. The slope becomes steep. Moreover, since the dome-shaped part 24 is formed of a material containing a light diffusing agent, it is possible to diffuse the light from each ring-shaped light source and reduce the luminance unevenness of the illumination light.

In this embodiment, light of the same color (for example, red light) is turned on to the ring-shaped light source by the LED 26 of the upper substrate 201 of the first illumination unit 2A and the upper substrate 201 of the second illumination unit 2B. Used as the first illumination light and the second illumination light for detection. On the other hand, each ring-shaped light source of the middle substrate 202 and the lower substrate 203 is turned on with color light other than red (for example, blue light), and this color light is used as illumination light for detecting a color defect. (Different colored light may be turned on for each of the substrates 202 and 203).
At the time of imaging, as will be described later, all the light sources are turned on to detect uneven defects and color defects at once.

  Next, FIG. 2 shows the relationship between the first illumination light and the second illumination light used for detecting the irregularity defect in the illumination light, and the relationship between the regular reflection areas of the illumination light.

  From the 1st illumination part 2A of this Example, the cross section is a rectangle and a diverging light is radiate | emitted as 1st illumination light. The first illumination light reaches the upper end portion of the short cylindrical portion 25 after passing through the hollow body 23, and light in a range corresponding to the size of the open end surface of the upper end portion enters the short cylindrical portion 25. Therefore, the first illumination light is irradiated onto the workpiece W after passing through almost the entire area of the short cylindrical portion 25 with sufficient intensity, and the light regularly reflected on the surface of the workpiece W enters the light receiving element 11 via the lens 10. .

Since the size of the regular reflection region 101 by the first illumination light is determined by the length of the short tube portion 25 and the position of the lens 10, the length of the short tube portion 25 is fixed if the position of the lens 10 is fixed. The shorter the length, the wider the regular reflection region 101 can be. Therefore, by shortening the length of the short tube portion 25 and widening the regular reflection region 101, it is possible to prevent the non-specular reflection region 103 from being generated between the regular reflection region 102 by the second illumination light. .

  Further, the light emitted from the ring-shaped light source of the second illuminating unit 2 </ b> A is irradiated to the inclined surface of the dome-shaped unit 24, diffuses, and propagates to the short tube unit 25. Further, light from the LED 26 outside the first wall portion 27a among the LEDs 26 of the upper substrate 201 also reaches the inclined surface of the dome-shaped portion 24 while being reflected by a mirror surface such as the second wall portion 27b or the hollow body 23. Therefore, the light emission luminance of the inclined surface is increased, and this is propagated to the short tube portion 25, so that the short tube portion 25 also emits light brightly. As a result, since the peripheral surface of the short cylinder part 25 also functions as a light emitting part for the second illumination light, the second end of the short cylinder part 25 is almost the same angle as the first illumination light passing therearound from the upper edge. Illumination light is emitted. As described above, by bringing the light emitting portions of the first illumination light and the second illumination light close to each other, the brightness of the surface of the workpiece W is also increased to the boundary of the regular reflection region 101 of the first illumination portion 2A or to the inside thereof. It becomes possible to irradiate high 2nd illumination light, and generation | occurrence | production of the non-regular reflection area | region 103 can be prevented more reliably. With such illumination, the specular reflection areas 101 and 102 by two types of illumination light can be continuously connected, so that the detection accuracy of the concavo-convex defect is improved in the entire range inside the boundary line of the outer specular reflection area 102. Can be secured.

  Although not shown in FIG. 2, the range irradiated with the light from each LED 26 of the middle board 202 and the lower board 203 is set so as to overlap the range including the regular reflection areas 101 and 102. Since the light from the substrates 202 and 203 is irradiated from the direction where the incident angle is larger than that of the second illumination light, the specularly reflected light hardly enters the camera 1 under the condition that there is no defect. However, if diffuse reflected light is strengthened or weakened due to the presence of color defects, the part where the reflected intensity changes appears in the image as a brighter or darker area than the surroundings. Can be detected.

  Next, the camera 1 and the illumination device 2 are supported by a robot 4 as shown in FIG. 3 in a state where the position and posture can be changed.

  This robot 4 has a structure in which four arm portions 42, 43, 44, 45 are connected to a base portion 41 in order via drive shafts c1, c2, c3, c4, respectively, at a predetermined height position. Suspended and fixed to. A holder portion 46 that indicates the camera 1 and the illumination device 2 is attached to the distal arm 45. In addition, in the illuminating device 2, 1st and 2nd illumination part 2A, 2B is arrange | positioned with the positional relationship shown in FIG.

  Although not shown in FIG. 3, the holder portion 46 is rotatably attached to the tip arm 45 by a shaft that rotates in the direction of the arrow in the drawing. The tip arm 45 is configured to be extendable and contractible.

  According to the above configuration, by controlling the rotation of the shafts c1 to c4 between the arm portions, adjusting the length of the tip arm 45, and controlling the rotation of the holder portion 46, the X axis (left and right direction in the figure), The camera 1 and the illuminating device are directed to an arbitrary position in a three-dimensional space represented by respective axes of the Y axis (the direction perpendicular to the drawing sheet) and the X axis (the vertical direction in the figure). 2 can be arranged. Therefore, even when the surface of the workpiece W is composed of surfaces having various curvatures, the camera 1 and the illumination device 2 are arranged with respect to each surface in the relationship shown in FIGS. Imaging can be performed under illumination suitable for detection.

  The alignment of the camera 1 and the illumination device 2 and the work W is not limited to the above example, and the position and posture of the work W may be changed. When only one surface of the workpiece W is to be inspected, alignment may be performed using an XY stage.

FIG. 4 is a block diagram of the defect inspection apparatus.
The defect inspection apparatus according to this embodiment includes a control processing apparatus 3 in addition to the camera 1, the illumination apparatus 2, and the robot 4. The control processing apparatus 3 includes a CPU 301, a memory 302, an input unit 303, an output unit 304, a light source control unit 305, a robot control unit 306, a camera control unit 307, an inspection image memory 308, a reference image memory 309, and a parameter storage memory 310. Etc. are provided.

The memory 302 stores a program for causing the CPU 301 to execute inspection and teaching processing.
The light source control unit 305 controls on / off of the light sources in the illumination units 2A and 2B and the amount of illumination light. The camera control unit 307 controls the imaging operation of the camera 1, and the robot control unit 306 controls the operation of the positioning robot 4 shown in FIG.

  The inspection image memory 308 stores a color image (hereinafter referred to as “inspection image”) generated by imaging the workpiece W to be inspected. Prior to the inspection, the reference image memory 309 stores a color image (hereinafter referred to as a “reference image”) generated by imaging a non-defective product model of the workpiece W under the same conditions as in the inspection. These inspection image and reference image are generated for each inspection region.

  The parameter storage memory 310 stores various parameters necessary for inspection. For example, setting data necessary for operation control of the robot 4, data for lighting control of the light source, a plurality of types of threshold values used for binarization processing and determination processing described later, and the like are stored. All of these parameters are set based on the measurement result for the non-defective product model of the workpiece W, the user's setting operation, and the like in the teaching mode prior to the inspection.

  The input unit 303 is used for inputting various data or performing a confirmation operation during the above teaching. The output unit 304 is for outputting the setting result and the inspection result, and is configured as an interface circuit to an external device and a monitor (not shown).

  Hereinafter, the flow of processing relating to inspection will be described with reference to FIG. Here, it is assumed that each light source in the illumination device 2 is turned on prior to the start of processing, and the lighting state is maintained until the inspection is completed.

  First, by controlling the operation of the positioning robot 4, the camera 1 and the illumination units 2 </ b> A and 2 </ b> B are aligned with the inspection area where the workpiece W is registered, and imaging is performed (steps 1 and 2). The image generated here is stored in the inspection image memory 308.

  Next, a reference image corresponding to the inspection area being processed is read from the reference image memory 309, and a difference grayscale image between the inspection image generated in the previous step and the reference image is generated (step 3). Specifically, for each color data of R, G, and B, a density difference between pixels having a correspondence relationship between images is obtained, and an average value of these density differences is calculated. As a result, grayscale image data representing the degree of difference in color or brightness with respect to the reference image is generated for the inspection image.

  After that, by binarizing the generated difference grayscale image with the registered threshold value, pixels whose color or brightness difference exceeds the threshold value are white pixels, and other pixels are black pixels. Cut (step 4). Further, the white pixels included in the binarized image are separated for each connected one, and a labeling process is performed for attaching different labels to the respective white pixel regions, and for each labeled region, The area and position of the region are measured (step 5).

  Thereafter, based on the measurement result, a region having an area of a predetermined value or more is recognized as a defect (step 6). Further, when a defect is recognized, the position and area of the corresponding region are recognized as the position and size of the defect.

  Thereafter, similarly, the above steps 1 to 6 are repeated for each registered inspection region. When the processing for all the inspection areas is completed (Step 7 is “YES”), the quality of the entire workpiece W is judged based on the inspection result of each inspection area (Step 8). Thereafter, in the final step 9, the determination result is output to a monitor or an external device (step 9), and the process is terminated.

It is a figure which shows the structural example of the optical system of a defect inspection apparatus. It is a figure which shows the irradiation state and reflection state of two types of illumination light used for a detection of an uneven | corrugated defect. It is a figure which shows the structural example of the robot for position alignment processes. It is a block diagram of a defect inspection apparatus. It is a flowchart which shows the process sequence in a test | inspection. It is a figure which shows the structural example of the conventional optical system. It is a figure which shows the problem at the time of making the optical path of the optical system of FIG. 6 long. It is a figure which shows the relationship of the regular reflection area | region which arises under the illumination state shown to FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Camera 2 Illuminating device 3 Control processing apparatus 2A 1st illumination part 2B 2nd illumination part 21 Light source 22 Half mirror 23 Hollow body 24 Dome-shaped part 25 Short cylinder part 26 LED
27 Wall 101, 102 Regular reflection area

Claims (6)

A first illuminating unit that irradiates light that travels along the optical axis while diverging around the optical axis within the field of view of the imaging device that is disposed with the light-receiving surface facing the target, the imaging device, and the target A second illuminating unit that irradiates light that travels in an oblique direction with respect to the optical axis of the imaging device and is disposed closer to the object than the first illuminating unit between the object and the object,
The second illuminating unit guides light emitted from the first illuminating unit to an object, and a light passage unit for guiding reflected light from the object to light from each illuminating unit to the imaging device, A ring-shaped light source arranged so as to surround the light passage part, and an inclined surface that is inclined so as to approach the object as it goes from the inside to the outside, is connected to the edge of the light passage part on the side close to the object over the entire circumference. And illuminating a region outside the range of illumination by the light exiting the first illumination unit and passing through the light passage unit by the light exiting from the ring-shaped light source and passing through the light exit unit. In the lighting device,
Light-passing section of the second lighting unit includes a first passage portion diameter farther from the first illuminating section together to have a receiving opening is conical which decreases accept divergent light from the first illumination unit, the first It is constituted by a short cylindrical second passing part that connects the 1 passing part and the light emitting part,
The divergent light from the first illumination unit that has entered the first passage through the receiving port travels through the first passage and reaches the first end of the second passage from the entire opening end surface on the first passage portion side. 2 Enter the passing section,
The ring-shaped light source includes a plurality of light emitters arranged along an outer peripheral surface in the vicinity of the receiving port of the first passage portion, and from a position corresponding to the ring-shaped light source to a light emitting portion. A wall that surrounds the area outside the ring-shaped light source is provided,
The light emitting portion is formed of a material containing a light diffusing agent, and the imaging device diffuses light reaching the light emitting portion from the ring light source through a space between the light passage portion and the wall portion. Lighting device that leads to the visual field of The second passage portion and the light emitting portion of the second illumination portion are integrally formed of a material containing a light diffusing agent, and the outer peripheral surface of the first passage portion and the inner peripheral surface of the wall portion of the light passage portion. The illuminating device according to claim 1, wherein a mirror finish is applied . The wall surface in a range from a position corresponding to the ring-shaped light source of the wall portion to a position away from the light emitting portion by a predetermined distance is formed on an inclined surface that is inclined so as to approach the first passage portion as the light emitting portion is approached . The lighting device according to claim 1 or 2, wherein Outside the wall of the second illuminating unit, a second ring-shaped light source including a plurality of light emitters that emit light having a wavelength range different from that of the first illuminating unit and the ring-shaped light source inside the wall. , At least one is arranged at a position closer to the light emitting part than the ring-shaped light source inside the wall part,
The illuminating device according to any one of claims 1 to 3, wherein the inclined surface of the light emitting portion continues to a position facing the outermost ring-shaped light source. An imaging device arranged with a light-receiving surface facing an inspection target, a first illumination unit that irradiates light that travels along the optical axis while diverging around the optical axis in the field of view of the imaging device; and An illuminating device including a second illuminating unit that is disposed between the imaging device and the object at a position closer to the object than the first illuminating unit and irradiates light traveling in an oblique direction with respect to the optical axis of the imaging device. And determining means for processing the image of the inspection object generated by the imaging device under illumination by each illumination unit of the illumination device to determine the presence or absence of irregularities on the surface of the inspection object,
The second illuminating unit guides light emitted from the first illuminating unit to an object, and a light passage unit for guiding reflected light from the object to light from each illuminating unit to the imaging device, A ring-shaped light source arranged so as to surround the light passage part, and an inclined surface that is inclined so as to approach the object as it goes from the inside to the outside, is connected to the edge of the light passage part on the side close to the object over the entire circumference. And illuminating a region outside the range of illumination by the light exiting the first illumination unit and passing through the light passage unit by the light exiting from the ring-shaped light source and passing through the light exit unit. Is,
Light-passing section of the second lighting unit includes a first passage portion diameter farther from the first illuminating section together to have a receiving opening is conical which decreases accept divergent light from the first illumination unit, the first It is constituted by a short cylindrical second passing part that connects the 1 passing part and the light emitting part,
The divergent light from the first illumination unit that has entered the first passage through the receiving port travels through the first passage and reaches the first end of the second passage from the entire opening end surface on the first passage portion side. 2 Enter the passing section,
The ring-shaped light source includes a plurality of light emitters arranged along an outer peripheral surface in the vicinity of the receiving port of the first passage portion, and from a position corresponding to the ring-shaped light source to a light emitting portion. A wall that surrounds the area outside the ring-shaped light source is provided,
The light emitting portion is formed of a material containing a light diffusing agent, and the imaging device diffuses light reaching the light emitting portion from the ring light source through a space between the light passage portion and the wall portion. Defect inspection equipment that leads to the field of vision. Outside the wall of the second illuminating unit, a second ring-shaped light source including a plurality of light emitters that emit light having a wavelength range different from that of the first illuminating unit and the ring-shaped light source inside the wall. , At least one is disposed at a position closer to the light emitting portion than the ring-shaped light source inside the wall portion, and the inclined surface of the light emitting portion continues to a position facing the outermost ring-shaped light source,
The determination means processes an image of the inspection object generated by the imaging device under illumination by light from the first illumination unit and light from each ring light source of the second illumination unit, and performs the inspection The defect inspection apparatus according to claim 5, wherein the presence or absence of irregularities and color defects on the surface of the object is determined.

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