JP5740595B2 - Outline detection method and outline detection apparatus - Google Patents

Description

  The present invention relates to a contour detection method and a contour detection device for detecting a contour of a workpiece.

  For example, when a shape inspection of a workpiece such as a semiconductor chip is performed, only the outer contour line of the workpiece is detected so that the shape can be specified and compared with a design value. When detecting the outline (edge) of the workpiece, the edge of the workpiece placed on the mounting table is illuminated from the surrounding area with low-angle light by an annular low-angle illumination as shown in Patent Document 1. Makes it easier to detect light from the edge of the camera.

  The contour detection apparatus 100A used for the contour detection will be described more specifically. As shown in FIG. 14, the surface of the mounting table is used as a background surface 6A, and a workpiece W is placed on the background surface 6A. A plurality of LEDs 21A are arranged in a ring shape, and a ring illumination 10A having a light emission direction directed substantially in the center of the ring is provided above the workpiece, and the central through-hole 4A of the ring illumination 10A is provided. The workpiece W is imaged by the camera 5A via

  By the way, when the height of the workpiece W is low, the ring illumination 10A is brought close to the background surface 6A so that the edge portion of the workpiece W is sufficiently illuminated, so that the perspective view of FIG. When the background surface 6A is viewed from above, the light irradiation region 7A is formed in which the background surface 6A in the through-hole 4A is illuminated in a substantially circular shape without a gap. Then, since illumination light is irradiated not only on the workpiece W but also on the background surface 6A around the workpiece W, when the background surface 6A is a material or surface shape that scatters light, as shown in FIG. Not only scattered light from the edge of the workpiece W but also scattered light from the background surface 6A around the workpiece W in the field of view of the camera 5A is detected by the camera. If the amount of scattered light from the background surface within the field of view of the camera increases, the difference in brightness between the scattered light from the edge of the workpiece W and the scattered light from the background surface 6A becomes difficult to occur as shown in FIG. The edge of W becomes difficult to detect. As described above, in the conventional contour detection method, particularly when the height of the workpiece is low, the amount of illumination light applied to the background surface around the workpiece increases, so that it is difficult to detect the edge of the workpiece. The problem becomes noticeable. Even when the workpiece has a certain height, it may be difficult to detect an edge due to scattered light from a background surface around the workpiece depending on the configuration of the ring illumination or the like. On the contrary, even if the influence of scattered light from the background surface is small, reflected light is generated from the entire surface of the workpiece, so that it is sometimes difficult to shine only the edge portion to be detected, particularly the outer contour line. In addition, if the edge portion of the workpiece is a curved surface such as an R surface, the reflected light from the edge portion has a width, which may be difficult to grasp as a contour line.

  Also, some contour detection devices for detecting the outer contour of a wafer in a chamber as shown in Patent Document 2 use ring illumination. In this contour line detection apparatus, as shown in FIG. 17, light polarized in a predetermined direction is irradiated from the ring-shaped illumination 10A onto the entire surface of the wafer W and the background surface around the outer contour line of the wafer W. Is configured to do. More specifically, a wafer W that reflects light while maintaining the polarization of the incident light is placed on the reflecting member 61A that changes its polarization when the light is reflected, and the ring shape The central axis of the through hole 4A of the illumination 10A is arranged so as to pass through the center of the wafer W with respect to the surface of the circular wafer W. Further, the light emitted from the ring-shaped illumination 10A is set so as to be irradiated so as to spread to the outside including all the outer contour lines of the wafer W. Then, the light passing through the through hole 4A out of the reflected light from the reflecting member 61A around the outer contour of the wafer W and the wafer W and serving as the background surface 6A is imaged through the polarizing filter 51A. Only the reflected light from either the wafer W or the reflecting member 61A is imaged, and the outer contour that is the boundary between the wafer W and the reflecting member 61A is detected. In addition, in this method of detecting the outer contour of the wafer W, for the purpose of preventing stray light and improving the contrast, the cylindrical light shielding member 3A is provided in the through-hole 4A in the center of the ring-shaped illumination 10A. The light 10A is also configured to shield light incident at a predetermined angle or more from the illumination 10A to the central axis side of its own through-hole 4A.

  However, in such a contour detection apparatus 100A, it is necessary to place a workpiece whose outer contour is to be detected on a special reflecting member 6A that reflects and reflects the polarization of incident light. Depending on the configuration and restrictions, it may be difficult to use. In addition, even though the polarizing filter 51A is used, when the material of the workpiece W and the material of the reflecting member 61A are similar and the tendency of polarization is similar, the ring illumination 10A to the workpiece W and the background Since both surfaces 6A are directly irradiated with illumination light, there arises a problem that a difference in luminance is unlikely to occur between the workpiece W and the background surface 6A as in the conventional case.

JP 2003-303511 A JP 2006-339254 A

  The present invention has been made in view of the various problems related to contour detection as described above, and it has been difficult to detect only the conventional contour line due to the influence of the background surface and the characteristics of the workpiece, An object of the present invention is to provide a contour detection method and a contour detection device capable of clearly detecting the contour of a workpiece even when the height is low and the influence of reflected light from the background is strong.

  That is, the contour detection method of the present invention is a contour detection method for detecting a contour of the workpiece by detecting light from the workpiece by a light detection unit, and the position where the light detection unit is provided Set above the workpiece, and the illumination light emitted from the light emitting section is substantially at a position spaced a predetermined distance outward from the detection target contour line, which is at least a part of the contour line, or the inner edge, or It is set to irradiate only the light irradiation region having an outer edge at a position separated from the detection target contour line by a predetermined distance, and the light irradiation region is lower than the detection target contour line and illuminated. It is set so that it may be formed on the surface where light is scattered.

  In addition, the contour detection device of the present invention is a contour detection device for detecting the contour of the workpiece by detecting light from the workpiece with a light detection unit, and is a light emission that emits illumination light. And a light detection unit that is provided above the workpiece and detects light from the workpiece, and the illumination light emitted from the light emission unit is substantially the outline of at least a part of the workpiece It is configured to irradiate only a light irradiation region having a position separated from the detection target contour line, which is a line, a predetermined distance outward as an inner edge, or having a position spaced a predetermined distance inward from the detection target contour line as an outer edge. The light irradiation area is formed below the detection target contour line and on a surface on which illumination light is scattered.

  Here, the surface on which the illumination light is scattered is a concept including not only a surface that scatters light over the entire surface but also a surface that scatters light at least in part or all of the light irradiation region. The detection target outline is not a concept including only a ridge line with an edge, but a concept including a line indicating a rounded corner. Further, the upper part of the work and the lower part of the work are not only the vertical direction but also the concept including the upper and lower sides as viewed from the surface on which the work is disposed with reference to the surface on which the work is disposed. For example, when a workpiece is arranged on a surface extending in the vertical direction, the horizontal direction corresponds to the top and bottom.

  In such a contour detection method and contour detection device, since the illumination light is not directly irradiated to the detection target contour of the workpiece and its vicinity, it is in the vicinity of the background surface of the detection target contour. Scattered light from the object is not generated. On the other hand, scattered light is generated in the light irradiation region formed on the surface below the detection target contour, and a part of the light is irradiated onto the detection target contour above the surface again. Since scattered light is generated, the detection target contour line of the workpiece can be illuminated even when the illumination light is not directly applied to the workpiece. Therefore, it is possible to shine only the detection target contour line of the workpiece without illuminating the vicinity of the detection target contour line, and a large luminance difference is generated between each. Therefore, the detection target contour line is clearly detected by the light detection unit. be able to. Further, since the light detection unit is provided above the workpiece, only the light scattered in the light irradiation region and further scattered in the detection target contour line of the workpiece and the traveling direction thereof is changed. It can be easily detected by the light detection unit.

  Furthermore, since it is configured so that only the edge is illuminated by the secondary light from the background surface irradiated with the illumination light, an illumination device is provided below the contour line to be detected, and the contour line is directly irradiated with light. There is no need to do. For example, it is conceivable to detect the contour line by irradiating direct light from below the detection target contour line without using secondary light, but when inspecting in a state where the workpieces are flowing in order by the belt conveyor Is difficult to apply in practice because it is necessary to arrange the light emitting part so as not to hinder the movement of the workpiece. More specifically, when inspecting a flowing work, the light emitting unit is separated from the work so that it does not contact while the work is moving, and the light emitting unit is below the work at the time of inspection. It is necessary to stop the work once at the inspection position and to move the light emitting part or the work up and down, etc. Then, a waiting time such as a work stop time or a time required to move the light irradiation unit is generated, so that the inspection time for one work becomes long and the inspection efficiency is lowered.

  On the other hand, if the contour detection is performed by applying light from below the detection target contour line with secondary light as in the present invention, the contour detection is performed in a state where the light emitting portion and the workpiece are separated from each other. Therefore, it is possible to inspect continuously without stopping the work flowing by the belt conveyor or moving the work or the light emitting part up and down. Accordingly, since it is possible to prevent the waiting time as in the case of using direct light, it is possible to continuously detect the contour line of the workpiece flowing with very high inspection efficiency. Moreover, since it is only necessary to arrange | position a light emission part and a light detection part above a workpiece | work or a belt conveyor, it is easy to introduce | transduce into the existing test | inspection line.

  As a specific method for irradiating illumination light only to the light irradiation region, the work is placed on a background surface where the illumination light is scattered, and one opening end is larger than the work. The other opening end is set to a height higher than the position where the light irradiation unit is provided, and the position of the one opening end is set to the background surface of the workpiece. It is set so as to surround the workpiece as viewed from the side where it is placed, and the one opening end and the background surface are separated from each other, and the separation distance is included in the illumination light emitted from the light emitting unit. What is necessary is just to set so that the light which goes inside rather than the inner edge of the said light irradiation area | region may be light-shielded by the said light-shielding member.

  In order to prevent the light scattered in the light irradiation region from being scattered again by the work and entering the light detection unit directly as stray light, the contrast between the work and the background surface is deteriorated. The position of the light detection unit may be set above the other opening end, and the inner peripheral surface of the light shielding member may be set as a non-reflective surface. If it is such, it can absorb substantially except the light scattered by the outline of the workpiece | work on the inner peripheral surface of the said light shielding member, and the light scattered by the side in which the said photon detection part is provided in the outline Can only detect.

  As a specific method for preventing the light scattered in the light irradiation region from being directly detected by the light detection unit, the light detection unit is a camera, and the field of view of the image pickup area is the work piece. And a background surface around the workpiece, and the size may be set smaller than the inner edge of the light irradiation region.

  As described above, according to the contour detection method of the present invention, the illumination light emitted from the light irradiation unit substantially enters the light irradiation region having the inner edge at a position separated from the contour of the workpiece by a predetermined distance on the background surface. The illumination light is not directly irradiated on the workpiece and the background surface around the workpiece, and the outline of the workpiece is illuminated with the scattered light from the light irradiation region. Can be. Therefore, only the outline of the workpiece can be shined strongly to facilitate detection, and the outline can be clearly detected even when the height of the workpiece is particularly low.

The schematic diagram which shows the structure of the outline detection apparatus which concerns on 1st Embodiment of this invention. The typical perspective view which shows the illuminating device in 1st Embodiment, and its light irradiation area | region. The schematic diagram of the image imaged with the outline detection apparatus of 1st Embodiment. The comparison figure of the outline detection result of the circular magnet by the conventional outline detection apparatus and the outline detection apparatus which concerns on 1st Embodiment. The comparison figure of the outline detection result of the nut by the conventional outline detection apparatus and the outline detection apparatus which concerns on 1st Embodiment. The schematic diagram which shows the structure of the outline detection apparatus which concerns on 2nd Embodiment of this invention. The schematic diagram of the image imaged with the outline detection apparatus of 2nd Embodiment. The schematic diagram which shows the structure of the outline detection apparatus which concerns on 3rd Embodiment of this invention. The typical perspective view which shows the outline detection apparatus which concerns on other embodiment of this invention. The schematic diagram which shows the outline detection apparatus which concerns on another embodiment of this invention. The schematic diagram which shows the outline detection apparatus which concerns on another embodiment of this invention. The schematic diagram which shows the embodiment in the test | inspection line of the outline detection apparatus which concerns on different embodiment of this invention. The comparative example with respect to the embodiment in the test | inspection line of this invention. The schematic diagram which shows the structure of the conventional outline detection apparatus. The schematic diagram which shows a state in case the height of a workpiece | work is low in the conventional outline detection apparatus. The schematic diagram which shows the image imaged with the conventional outline detection apparatus, when the height of a workpiece | work is low. The schematic diagram which shows the outline detection apparatus for detecting the outer outline of the wafer in the conventional chamber.

  Hereinafter, a first embodiment of the present invention will be described with reference to the drawings.

  A configuration of the contour detection apparatus 100 used in the contour detection method of the present embodiment will be described with reference to FIG. The contour line detection device 100 is used when, for example, performing shape inspection of a workpiece W such as a semiconductor chip, and is used for imaging the workpiece W with the camera 5 and detecting the contour from the edge portion. Is. In the present embodiment, the detection target contour line is set to an outer contour line indicating the outer shape of the workpiece W.

  As shown in FIG. 1A, the contour detection device 100 is provided directly on the background surface 6 that is the surface of the mounting member on which the workpiece W is mounted and the workpiece W arranged on the mounting table. A ring-shaped illumination device 10 having an observation hole 4 in the center, and a camera 5 provided above the work W so as to capture the work W in the field of view through the observation hole 4 It is.

  The background surface 6 on which the workpiece W is placed has an opaque surface, and is formed of a surface shape and a material in which incident light is diffused almost in all directions to generate scattered light. More specifically, the background surface 6 is, for example, an opaque resin surface, a satin metal surface, a surface of a mesh-like background member, or the like, and a surface on which secondary reflection occurs. Further, the workpiece W is smaller than the vertical and horizontal dimensions and has a flat shape. Note that this workpiece W is merely an example, and the contour detection device 100 of the present embodiment may be used when detecting an outer contour even if the workpiece W has other shapes.

  The illumination device 10 will be described with a focus on the shape. As shown in the perspective view of FIG. 1B, the light emitting portion 2 having a substantially flat cylindrical shape and a thin cylindrical shape protruding from the central portion of the flat cylindrical shape. The light shielding member 3. That is, the illumination device 10 is configured to be rotationally symmetric with respect to the central axis of the observation hole 4, and the vertical axis with respect to the center of the workpiece W and the central axis of the observation hole 4 Are provided so as to match. More specifically, the illuminating device 10 includes a light emitting portion 2 in which a plurality of light emitters 21 that emit illumination light are annularly arranged, and a cylindrical shape provided along the inside of the light emitting portion 2. The light shielding member 3 is configured so that the illumination light is irradiated only on the light irradiation region 7 having an inner edge at a position separated from the contour of the workpiece W on the background surface 6 by a predetermined distance. Here, the distance between the contour of the workpiece W and the light irradiation region 7 is such that only the edge of the workpiece W is shined by scattered light from the light irradiation region 7 described later, and a sufficient amount of light is obtained. It is set. More specifically, it suffices that a slight gap is generated between the detection target contour line and the inner edge of the light irradiation region 7, and the vertical separation distance between the light shielding member 3 and the background surface 6 is sufficient. And can be determined based on the height of the workpiece. For example, when the workpiece W is taller than the vertical separation distance between the light shielding member 3 and the background surface 6, the light scattered in the light irradiation region 7 reaches the edge of the workpiece W. Therefore, it is preferable that the distance between the detection target contour line and the light irradiation region 7 in the horizontal direction is small. In the opposite case, contour detection can be performed even if the horizontal separation distance is large.

  The luminous body 21 is a bullet-type LED 21 and emits light having a spread according to the orientation characteristics from the light exit end. Each LED 21 is provided in two rows side by side on virtual circles with different diameters, and the LEDs 21 are arranged so that the optical axis of each LED 21 is in the axial direction of the observation hole 4, that is, in the installed state, downward in the vertical direction. is there.

  The light shielding member 3 has a cylindrical shape whose opening end is configured to be larger than the workpiece W. When the background surface 6 is viewed from the side where the workpiece W is disposed, one opening end 32 is In addition to being provided so as to surround the workpiece W, the opening end 32 and the background surface 6 are separated from each other when viewed from the horizontal direction. Here, since the opening end is configured to be larger than the workpiece W, specifically, the area determined by the inner contour of the opening end when viewed from above the background surface 6 is the outer contour of the workpiece W. It is designed to be larger than the determined area. Further, the separation distance between the opening end and the background surface 6 is the length when a perpendicular is dropped from the tip of the opening end to the background surface 6. The separation distance is set so as to block light traveling inward from the inner edge of the light irradiation region 7. Therefore, as shown in white in the perspective view of FIG. 2, the illumination light irradiated from the illumination device 10 to the background surface 6 is irradiated so that the light irradiation region 7 is formed in an annular shape. Become. Further, the separation distance is set so that the amount of scattered light entering the light shielding member 3 is sufficient to make the contour of the workpiece W shine, and no extra light is incident from the outside. is there. In addition, when the inspection object is continuously inspected on a line in which inspection objects flow one after another, the height of the back of the workpiece becomes larger if the position of the ring illumination is fixed. It may be determined in consideration of conditions.

  The other opening end 33 is located above the light emitting portion 2 so that the illumination light does not enter the cylinder directly from above. Further, the inner peripheral surface 31 of the light shielding member 3 is, for example, painted black to be a non-reflective surface, and light incident on the inner peripheral surface 31 is absorbed.

  The camera 5 corresponds to the light detection unit in the claims, is provided above the other opening end 33, and images the workpiece W and the surrounding background surface 6 through the observation hole 4. It is. The field of view is such that the radius from the center of the workpiece W does not reach the inner edge of the light irradiation region 7. That is, it is set so as to capture an area narrower than the hatched area at the center of the background surface 6 shown in the perspective view of FIG.

  With reference to the schematic diagram of FIG. 1 (a) and the perspective view of FIG. 2, how the illumination light and its scattered light act to detect the workpiece W by the contour detection device 100 configured as described above. While explaining.

  First, the illumination light emitted from the light emitting unit 2 travels while spreading vertically downward at a predetermined angle. At this time, the illumination light traveling to the workpiece W and the background member around the workpiece W is blocked by the light shielding member 5 inside the light emitting portion 2. Therefore, as shown in the perspective view of FIG. 2 and the like, an annular light irradiation region 7 having an inner edge at a position separated from the contour of the workpiece W by the light emitting portion 2 and the light shielding member 3 is the background. Formed on surface 6. On the other hand, since the illumination light is not directly applied to the workpiece W and the background surface 6 around the workpiece W, it is a dark region as shown by hatching in FIG.

  Next, as shown in FIG. 1A, when the light irradiation region 7 is irradiated with illumination light, since the background surface 6 is a scattering surface, omnidirectional diffusion occurs, and the light irradiation region 7 is secondary. It will function as a light source. Here, the light scattered by the illumination light 7 in the light irradiation region 7 is referred to as secondary light.

  In the light irradiation region 7, omnidirectional diffusion occurs, so that some of the secondary light passes between the tip of the light shielding member 3 and the background surface 6. Since the workpiece W is on the upper side with respect to the background surface 6, a part of the secondary light that has passed through the gap is a side surface or an outline of the workpiece W as indicated by a two-dot chain line in FIG. Reach the edge to form from below. On the other hand, the secondary light that has not reached the workpiece W is incident on the inner peripheral surface 31 of the light shielding member 3 and absorbed as shown by the one-dot chain line in FIG.

  When attention is paid to the secondary light indicated by the two-dot chain line reaching the edge portion, the secondary light is again scattered at this edge. Here, the light in which the secondary light is scattered at the edge portion of the workpiece W is referred to as tertiary light. Of the tertiary light, the light scattered upward with the camera 5 as indicated by a thick solid line can be detected by the camera 5, and the light scattered in other directions (not shown) is the light shielding member. 3 is absorbed by the inner peripheral surface 31.

  As described above, in this contour line detection method, the light irradiation is not performed directly on the workpiece W and the background surface 6 surrounding the workpiece W, but on the position away from the contour of the workpiece W. Only the area 7 is irradiated with illumination light to form a secondary light source, and the contour of the workpiece W is illuminated with secondary light as indicated by a two-dot chain line that proceeds upward at a low angle therefrom. Since the secondary light is detected by the camera 5 as shown by a thick solid line generated by scattering the secondary light at the contour of the work W, the background around the work W as shown in FIG. The surface 6 can be imaged by illuminating only the outline of the workpiece W without illuminating it.

  Therefore, even when the height of the workpiece W is particularly low, the contrast between the contour of the workpiece W and the background surface 6 can be increased, and the contour detection accuracy can be improved.

  Further, among the secondary light from the light irradiation region 7, the light that is not reflected by the work W is absorbed by the inner peripheral surface 31 of the light shielding member 3, so that it enters the camera 5 as stray light, It is possible to prevent the entire captured image from becoming bright and the contrast with the contour portion from being deteriorated.

  In addition, by illuminating the background surface 6 below the edge that is the detection target contour line of the workpiece W to form a light irradiation region 7, the secondary light illuminates the edge from below. Therefore, for example, it is only necessary to install a ring illumination and a camera above an existing inspection line, and the introduction is easy. In other words, in a line such as an existing belt conveyor, it is possible to avoid a problem that it is very difficult to install a ring illumination or the like in order to directly irradiate a work with light from below from a problem such as a space. Moreover, the material of the member used as the background surface 6 should just scatter light, and since there are few restrictions on a background member, it is easy to use it for various uses. In addition, even if the background color is black, for example, if the glossy black or the like is scattered, only the edge of the workpiece W can be illuminated to detect the contour line.

  Next, an experimental result of contour detection using the contour detection apparatus 100 according to the first embodiment will be described in comparison with a detection result obtained using the conventional contour detection apparatus shown in FIG. In this example, the workpiece W is somewhat higher than the above-described example.

  First, the case where the outline of a magnet having a cylindrical shape and a black surface is detected will be described. This magnet has a rough surface, and has a small reflectance of light from an edge (intersection of the upper surface and the side surface) which is a contour portion. The background surface was imaged when the grid portion was a white mesh background and when it was blank.

  4 (a) and 4 (b) show the contour detection results of the magnet by the conventional contour detection apparatus 100A. As shown in FIG. 4 (a), in the hole portion of the mesh ground (the black portion on the background surface), although linear light can be slightly imaged from the edge portion of the magnet, It can be seen that it is difficult to detect only the contour line because the contour of the magnet on the white surface on the background surface has almost no difference in luminance. Also, as shown in FIG. 4B, when the background surface is a blank sheet, the reflectance of the background surface is high, so the difference between the blank sheet and the entire magnet can be understood, but the blank sheet and the inside of the magnet outline are also shining. Therefore, it can be seen that imaging is not possible with the edge portion of the magnet being linear. Therefore, it can be seen that in both examples, when the reflected light from the background surface is strong, only the contour of the workpiece W cannot be detected well.

  On the other hand, as shown in FIG. 4C and FIG. 4D, when imaging is performed under the same conditions using the contour detection device 100 of the first embodiment, only the edge portion of the magnet can be illuminated, It turns out that it can detect as a line. As described above, the light is not directly irradiated on the workpiece W and its surroundings, and only the secondary light from the light irradiation region 7 hits the edge and is further scattered and detected as the tertiary light. It is thought that it is because.

  Furthermore, an experimental result in the case where the workpiece W is made of a metal nut under the same conditions as the background surface will be described in comparison with a conventional example. Since this nut is a metal, the reflectance from the edge portion is high, the edge portion is an R surface, and a screw hole for screwing a screw is formed in the center portion.

  As shown in FIGS. 5 (a) and 5 (b), when this nut is imaged by the conventional contour detection device 100A, the light from the edge portion is used regardless of whether the background surface is mesh ground or white paper. However, since the edge is rounded, the outline becomes thick and the thickness varies depending on the location. Therefore, when the contour is detected by image processing or the like, a certain amount of error may occur because the contour is thick. Moreover, since there is reflected light from the screw hole portion, a contour line also appears on the inner side. If the screw hole portion is also imaged in this way, there may be a problem when only the outer contour that is the outermost contour is detected.

  On the other hand, as shown in FIGS. 5C and 5D, according to the contour detection apparatus 100 of this embodiment, only the outer contour can be imaged in a thin line shape on any background surface. I understand that Moreover, since the secondary light generated by scattering in the light irradiation region does not hit the inner thread portion as is apparent from FIG. 1 and the like, it can be seen that the thread portion is hardly imaged. That is, according to the contour detection apparatus 100 of the present embodiment, it can be suitably used even when it is desired to detect only the outermost outer contour when there are a plurality of contour lines.

  Next, a second embodiment will be described. In addition, the same code | symbol shall be attached | subjected to the member corresponding to 1st Embodiment.

  In the first embodiment, a part of the illumination light emitted from the light emitting unit 2 is blocked by the light shielding member 3 so that the illumination light is irradiated only to the annular light irradiation region 7 on the background surface 6. However, for example, the illumination light may be configured to reach only the light irradiation region 7 directly from the light emitting unit 2 without using the light shielding member 3.

  More specifically, as shown in FIG. 6, the light emitting ends of the plurality of LEDs 21 constituting the light emitting portion 2 are provided so as to face outward with respect to the central axis of the observation hole 4. The background surface 6 around the W and the workpiece W may not be irradiated with illumination light. For example, the LED 21 may be arranged side by side on an annular flexible substrate, and both ends of the flexible substrate may be brought into contact with each other so that the light emission end of the LED 21 is on the outside and rounded into a truncated cone. Good.

  The field of view of the camera 5 may be imaged so as to include a part of the light irradiation region 7, for example. Even when an image is captured in such a visual field in the second embodiment, the edge of the workpiece W can be detected as shown in FIG. When it is desired to further improve the contrast, the field of view may be set to be narrower and less affected by scattered light from the outer light irradiation region 7.

  Next, a third embodiment will be described. In addition, the same code | symbol shall be attached | subjected to the member corresponding to 1st Embodiment.

  In the contour detection device 100 of the third embodiment, the light emitter 21 constituting the light emitting portion 2 is provided to be inclined toward the observation hole 4 side, and light is emitted only in the vicinity of the distal end side opening end 32 of the light shielding member 3. The point which is made to form the irradiation area | region 7, and the point by which the outer side surface 34 of the said light shielding member 3 is a mirror surface differ from the light shielding member 1st Embodiment.

  More specifically, the LEDs constituting the light emitting section 2 are arranged inside a flexible substrate rounded into a truncated cone, and the optical axis is directed toward the observation hole 4 as shown in FIG. It is like that. Furthermore, two rows of LEDs are arranged in an annular shape, and the inclination angle with respect to the horizontal plane of the outer LED is larger than that of the inner LED. In this way, the light irradiation region 7 is configured to concentrate in a narrow region as compared with the first embodiment.

  In addition, by using the outer surface 34 of the light shielding member 3 as a mirror surface, in the first embodiment, wasted light is reflected and reaches the light irradiation region 7. More specifically, since the light emitted from the light emitter 21 is reflected without being absorbed by the light shielding member 3, light is emitted from the light emitter 21 to the light irradiation region 7 with the light amount loss being minimized. can do. Therefore, since the amount of light scattered in the light irradiation region 7 is also increased, the amount of secondary light reaching the edge portion of the workpiece W can be increased, and the edge portion can be further illuminated by the tertiary light, The brightness can be increased to make it easier to detect the contour.

  Other embodiments will be described.

  In each said embodiment, the ring illumination 10 was cylindrical shape, and the shape of the light irradiation area | region 7 was also annular shape, However, Other shapes may be sufficient. That is, as shown in FIG. 9A, a substantially truncated cone shape may be used in which the camera side is the bottom surface side and the workpiece W side is the tip side. Even with such a shape, it is possible to form the light irradiation region 7 having the inner edge at a position spaced a predetermined distance from the contour of the workpiece. Moreover, as shown in FIG.9 (b), the ring illumination 10 may be square. More specifically, the ring illumination 10 has a square shape and the observation hole 4 has a square shape, and the light irradiation region 7 is formed in a substantially square shape. In this case, if the shape of the workpiece W is square, the distance from each side of the workpiece W to the light irradiation region 7 can be made equal, and the luminance of each side can be made uniform. Moreover, even with the ring illumination 10 of FIG. 9B, only the outer contour of the circular workpiece W can be detected.

  Although the inside of the outer contour is generally flat, the workpiece may have a multistage shape with the center portion further protruding as shown in FIG. 8, for example. In this case, in order to detect the outermost edge, the distance between the position of the light irradiation region and the open end of the light shielding member and the background surface is adjusted so that only the edge of the outer contour is detected. What is necessary is just to make it the next light reach | attain and block the light which goes to an inner edge part with the said light-shielding member. In addition, when it is desired to use the inner contour of the multi-stage workpiece as the detection target contour, the surface of the workpiece W is covered with a light shielding member as shown in FIG. Alternatively, the contour line may be detected by irradiating light from ring illumination to form the light irradiation region 7 on the surface of the workpiece W. That is, the light irradiation region 7 may be formed not only on the surface of the mounting member which is a member other than the workpiece but also on the workpiece itself or other objects other than the mounting member. . In short, the light irradiation region is formed below the detected detection target contour line, and it is only necessary that the formed surface is a surface that scatters light.

  In addition, as shown in FIG. 11, when the workpiece W is, for example, a flat plate-shaped ring and it is desired to detect an inner contour line, the inner contour line that is a detection target contour line is further inward. The contour line may be detected by forming the light irradiation region so that the position separated by a predetermined distance is the outer edge. In addition, the code | symbol attached | subjected to FIG. 11 attaches | subjects the same number to the thing corresponding to the thing attached | subjected to the said 1st Embodiment. Such a contour detection device can be suitably used when it is desired to illuminate only an annular member, for example, an inner contour line of a nut or the like.

  In addition, light is not irradiated around the workpiece by the light shielding member so that only the edge portion is shined by the secondary light, but light such as black is absorbed and scattered only in the vicinity of the workpiece. The material may be made of a material that does not cause the light, and the background surface other than the vicinity of the workpiece may scatter light. In this way, even if the light irradiation region cannot be strictly set by the light shielding member, scattered light does not occur from the vicinity of the workpiece, so that the accuracy of edge detection can be easily improved. More specifically, in the inspection line as shown in the plan view and the top view of FIG. 12, a black print B having a predetermined radius is applied to the surface of the belt conveyor CN having a scattering surface at regular intervals. Inspection accuracy may be improved by placing a work in the center of the circle. Further, in each of the contour detection devices 100 as shown in FIGS. 1, 6, 8, 10, and 11, the tip of the light shielding member and the workpiece W are separated from each other. The contour can be detected without moving up and down only the entire apparatus or only the constituent devices such as the light shielding member 3 and the camera 5 so as not to interfere with movement by contact. For this reason, while the workpiece W flows smoothly by the belt conveyor CN, when the workpiece W reaches the inspection position, the ring illumination 10 can be illuminated like a flash to continuously detect the entire outer contour line of each workpiece.

  As a comparative example of this embodiment, as shown in FIG. 13, direct light from the ring illumination 10 </ b> A is irradiated from below on the outer contour line of the workpiece W without using secondary light in the inspection line using the belt conveyor CN. Consider the case of detecting the entire circumference of an outer contour line. The operation of the inspection by the contour detection apparatus 100A using such direct light will be described. First, as shown in FIG. 13A, the work W is located directly below the camera 5A that is the inspection position in the contour detection apparatus 100A. Moving. Next, the belt conveyor CN is stopped as shown in FIG. 13B, and the ring illumination 10A is moved below the detection target contour line of the workpiece W as shown in FIG. Directly irradiate light. When the contour line is detected, the ring illumination 10A is moved upward as shown in FIG. 13D, and then the belt conveyor CN is moved again as shown in FIG. Will repeat. In this way, if it is intended to detect the contour line by directly illuminating the detection target contour line of the workpiece W from below in the inspection line, contact between the workpiece W and the contour line detection is prevented, and the movement of the workpiece W is prevented. A mechanism that prevents it from being obstructed is required. Moreover, as shown in FIGS. 13B to 13D, the time during which the workpiece W is stopped and the time required to move the ring illumination up and down are waiting times, so one workpiece is inspected. It takes a long time to do. That is, the inspection efficiency cannot be improved because the inspection cannot be performed while always moving without stopping the workpiece. For example, when detecting only a part of the outline of a workpiece, the lighting device may be fixed to the side of the belt conveyor and the inspection may be performed continuously. If it is attempted to detect the entire circumference of the outer contour line, it is necessary to place the illumination device also on the workpiece traveling direction side, so the workpiece or the illumination device must be moved up and down so as not to prevent movement. Then, since the waiting time described above occurs, the inspection efficiency is lowered.

  On the other hand, according to the contour detection device 100 of each embodiment, since the workpiece W and the contour detection device 100, in particular, the workpiece W and the light shielding member 3 are separated in the vertical direction, the workpiece W is moved by the belt conveyor CN or the like. Even when moving, if nothing is done, no contact occurs and movement is not hindered. In addition, since the outer contour line is irradiated with light from the lower side of the detection target contour line by the secondary light from the background surface, the work W is stopped or the work W or the illumination device 10 is moved up and down during the inspection. There is no need to Therefore, the workpiece contour line can be continuously detected without stopping the belt conveyor for the inspection, so that the waiting time as described above does not occur, and the inspection efficiency can be remarkably improved. .

  The method of irradiating light only to the light irradiation region is not particularly limited to each of the embodiments described above. For example, the background surface is irradiated in an annular shape with highly directional illumination light, and the light of the central portion is irradiated. You may make it mount a workpiece | work on the part which is not irradiated.

  The background surface may be any material that scatters light, and is not limited to a material that diffuses uniformly in all directions. For example, scattering that is biased from the light irradiation region toward the workpiece may be used.

  The background surface is not limited to a flat surface, and may be a curved surface having the highest point on which the workpiece is placed, for example. In short, it is sufficient that the light scattered from the light irradiation region does not enter the background surface around the workpiece. In such a background surface, only the edge portion can be lit to increase the contrast. it can. In other words, at least the background surface on which the light irradiation region is formed needs to be at a position lower than the workpiece, and only the edge of the workpiece can be illuminated by the scattered light. In addition, the background surface is not limited to the surface of the mounting table, the substrate, or the like, but refers to the surface on the back side of the workpiece whose contour is to be detected.

  In each of the above embodiments, contour detection is performed for shape inspection, but it may be used for inspecting whether or not a part is placed at a predetermined position, or may be used for other purposes. I do not care. In addition, although a camera is used as the light detection unit, a light receiving element such as a CCD or a CMOS may be used.

  In addition, various modifications and combinations of embodiments may be performed without departing from the spirit of the present invention.

DESCRIPTION OF SYMBOLS 100 ... Contour detection apparatus 2 ... Light emission part 21 ... Light-emitting body 3 ... Light-shielding member 31 ... Inner peripheral surface 32 ... One opening end 33 ... The other opening end 5 ... Camera (light detector)
6 ... Background W ... Workpiece

Claims (8)

A contour detection method for detecting a contour of the workpiece by detecting light from the workpiece with a light detection unit,
A position where the light detection unit is provided is set above the workpiece,
The position where the illumination light emitted from the light emitting portion is substantially spaced apart from the detection target contour line, which is the contour line of at least a part of the workpiece, by a predetermined distance is set as the inner edge, or the inner side from the detection target contour line It is set to irradiate only the light irradiation area with the outer edge at a position separated by a predetermined distance to
The light irradiation area is set to be formed on a surface below the detection target outline and on which illumination light is scattered, and between the workpiece and the light irradiation area on the surface. An outline detection method, wherein a region not irradiated with illumination light is formed . Place the work on a background surface where the illumination light is scattered,
Further using a cylindrical light shielding member whose one open end is larger than the workpiece,
Set the position of the other opening end to a height higher than the position where the light irradiation unit is provided,
The position of the one opening end is set so as to surround the workpiece as viewed from the side on which the workpiece is placed,
The one opening end and the background surface are separated from each other, and the light that travels inward from the inner edge of the light irradiation region among the illumination light emitted from the light emitting portion is caused by the light shielding member. The contour detection method according to claim 1, wherein the contour is set so as to be shielded from light. Set the position of the light detection unit above the other opening end,
The contour detection method according to claim 2, wherein an inner peripheral surface of the light shielding member is set as a non-reflective surface.   The light detection unit is a camera, and the field of view that is the imaging range is set so as to include the work and a background surface around the work, and the size thereof is larger than the inner edge of the light irradiation region. The contour detection method according to claim 1, 2 or 3. An outline detection device for detecting an outline of the workpiece by detecting light from the workpiece by a light detection unit,
A light emitting part for emitting illumination light;
A light detector provided above the workpiece and detecting light from the workpiece;
The position where the illumination light emitted from the light emitting portion is substantially spaced a predetermined distance outward from the detection target outline that is the outline of at least a part of the workpiece is used as the inner edge, or from the detection target outline It is configured to irradiate only the light irradiation area with the outer edge at a position spaced a predetermined distance inward,
The light irradiation region is formed on a surface below the detection target contour line and on which illumination light is scattered, and illumination light is irradiated between the workpiece and the light irradiation region on the surface. contour detecting apparatus characterized by being configured to so that is formed a region which is not. A cylindrical light-shielding member having one open end larger than the workpiece;
The position of the other opening end is set to a height equal to or higher than the position where the light irradiation unit is provided,
The position of the one opening end is set so as to surround the work as viewed from the side where the work is placed on the background surface on which the work is placed,
The one opening end and the background surface are spaced apart from each other, and light that travels inward from the inner edge of the light irradiation region among the illumination light emitted from the light emitting portion is shielded from light. The contour detection apparatus according to claim 5, wherein the contour detection apparatus is set to be shielded from light by a member. The position of the light detection unit is set above the other opening end,
The contour detection apparatus according to claim 6, wherein an inner peripheral surface of the light shielding member is a non-reflective surface. The light detection unit is a camera, and the field of view that is the imaging range is set so as to include the work and a background surface around the work, and the size thereof is larger than the inner edge of the light irradiation region. The contour line detection device according to claim 5, 6 or 7.