Inspection system and inspection procedures

Abstract

Inspection system (1) for checking elongated workpieces (2), in particular injection-molded parts such as pipette tips, which have a workpiece longitudinal axis (2a), comprising: - a holding device (3) for holding at least one or a plurality of workpieces (2) to be inspected, which are preferably arranged on the holder (3a) in several rows separated from each other by a distance d, - a lighting device (4) comprising at least one light source (4a), - at least one optical detection means (6), wherein the workpiece (2) is arranged in the beam path of the light emitted by the light source (4a) between the light source (4a) and the optical detection means (6), and wherein the optical detection means (6) detects the image of the workpiece produced by the lighting device (4), - an optical system (5) for directing the light emitted by the light source (4a) preferably laterally onto the workpiece (2) to be inspected, which is arranged on the holder (3a), and from the workpiece (2) onto the optical detection means (6), - preferably an evaluation device (7) which is connected to the optical detection means (6) via signal transmission and enables evaluation of the workpiece image, characterized in that (i) that the holding device (3) has at least two spaced-apart rows of holders for at least one or exactly one workpiece (2), and that a light deflection device (5n) is provided between the workpiece (2) and the detection means (6), which directs the shadow images (73) of two workpieces from different rows onto the detection means (6), and / or (ii) that the holding device (3) has at least two spaced-apart rows of supports for at least one or exactly one workpiece (2) each, and that a beam path splitter (5s) is provided between the light source (4a) and the workpiece (2), which divides the beam path (S) of the light source (4a) and preferably directs it simultaneously to different rows.

Description

[0001] The invention relates to an inspection system according to the preamble of claim 1 and an inspection method using such an inspection system.

[0002] Inspection systems are used, in particular, to perform quality checks on elongated injection-molded parts immediately after their production. Such parts are used, for example, in the medical field, such as pipette tips, cup-shaped containers for medical samples or substances to be analyzed, and the like. These parts must be manufactured with very high precision, as otherwise the work processes carried out using them, such as analytical procedures, would be impaired. For example, defects can occur in injection-molded parts, such as unwanted burrs, indentations, irregularities in the workpiece geometry due to warping, and, in particular, insufficiently filled areas, leading to the rejection of such parts.The inspection system is therefore subject to high demands regarding the detection of defective workpieces.

[0003] Furthermore, inspection systems of this type are often an integrated component of an automated production line, which typically extends from the production of workpieces in a mold, such as an injection molding machine, through workpiece inspection, to the packaging of the workpieces. High production speeds, however, necessitate correspondingly short inspection times for each workpiece using the inspection system. Therefore, the inspection system must be integrable into such a production system. Additionally, the inspection system must have a compact design, as the workpieces are often positioned close together on the fixture and / or limited installation space is available.

[0004] From DE 10 2017 120 376 B3, an inspection device is known in which the respective workpieces can be inspected as they pass through the device. This inspection device has a concave mirror arrangement to capture an image of the workpiece's outer surface reflected in the mirror using a camera. However, a disadvantage of this device is that the resulting mirror image of the workpiece exhibits greater optical distortions compared to the actual workpiece, leading to unreliability of the inspection method. Dimensional inspections and measurements are only possible to a very limited extent, if at all, with this concave mirror arrangement.Furthermore, it has been shown that the use of a mirror image of the workpiece under investigation is disadvantageous for certain applications and that certain workpiece defects, such as minor burrs, inaccuracies in the opening of the pipette tip or, in particular, surface defects such as inadequate injection of workpiece areas, are not always sufficiently detected.

[0005] US patent 2020 / 0376672A1 discloses an inspection system in which multiple light sources from different directions create shadow images of an object, which are captured by a camera.

[0006] JP 2000-18919 A ​​discloses an inspection system in which a shadow image of an object produced by a light source is captured by a camera.

[0007] DE 2617457 A1 discloses an optical testing device for objects, in particular made of glass, comprising a light source for directing more than one light beam onto an object to be tested, a first and a second reflector device and an optical receiving device, wherein the reflector devices are arranged such that they transmit the light beams transmitted through the object to the optical receiving device and wherein at least one first light beam and one second light beam strike the object at different angles.

[0008] US Patent 2021 / 0181223 A1 discloses a device for determining the position and / or extent of a droplet in a positioning chamber, wherein the device comprises a camera with a lens and a beam splitter in the camera's field of view, and wherein the device is designed such that light from the positioning chamber can enter the camera lens along a first light path as well as along a second light path. The invention thus aims to provide a generic inspection system that partially or completely overcomes the described disadvantages, enables particularly reliable detection of workpiece defects, and is cost-effective. Furthermore, the invention aims to provide a corresponding inspection method for verifying workpieces.

[0009] This problem is solved by an inspection system according to claim 1, and by an inspection method according to claim 24. Preferred embodiments of the invention are set forth in the dependent claims.

[0010] According to a first variant (i) of the invention, the holding device has at least two spaced-apart rows of holders for at least one or exactly one workpiece (2), wherein a light deflection device is provided between the workpiece and the detection means, which directs the shadow images of two workpieces from different rows onto the detection means.

[0011] According to a second variant (ii) of the invention, the holding device has at least two spaced-apart rows of holders for at least one or exactly one workpiece each, wherein a beam path splitter is provided between the light source and the workpiece, which divides the beam path of the light source and preferably directs it simultaneously onto different rows.

[0012] Variants (i) and (ii) are particularly preferred when implemented in combination.

[0013] The inspection system according to claim 1 preferably further comprises an optical system which, when the workpiece is irradiated with the light source of the lighting device, generates a shadow image of the workpiece, preferably an undistorted shadow image, from at least one direction transverse to the longitudinal axis of the workpiece, and which projects the generated shadow image onto the detection means, preferably undistorted, or which is designed for this purpose.

[0014] It has been found in the course of the invention that by generating a shadow image of the workpiece using the optical system, various workpiece defects, such as insufficient injection molding of surface component areas, particularly in the area of ​​an end section of the respective workpiece, such as a tip or a bottom area, can be detected with exceptional reliability. The shadow image exhibits very high contrast, namely a darker or dark / black shadow image compared to the surrounding, lighter area of ​​the workpiece environment, which enables particularly reliable inspection. Insufficient surface injection molding can be identified as a missing area at the edge of the shadow image. Burrs, local protrusions, film deposits of excess material, or other irregularities are also particularly easy to detect.Such workpiece defects, especially in injection-molded parts, can be detected with exceptional reliability and sharpness by the workpiece shadow image due to its high light / dark contrast with the adjacent image area. This is particularly true for the free end of the workpiece, the part facing away from the workpiece holder, such as the area of ​​a pipette tip opening. Furthermore, tolerance deviations in the workpiece geometry can be detected with exceptional reliability by the shadow image. This is especially true for the area of ​​the aforementioned free end of the workpiece, such as the area of ​​a pipette tip opening or the bottom of a container.

[0015] It has been found that, due to the high contrast of the shadow image to the surrounding image area, particularly short inspection times for the workpiece or exposure times are possible, which can even be in the range of a few microseconds. The inspection system can therefore be used particularly advantageously in an automated production line for manufacturing the workpiece, whereby the process speed of the production line is only very slightly or not at all reduced during the workpiece's passage through the inspection system, meaning that the production line can be operated continuously at high speed without this affecting the sharpness of the generated shadow image or its evaluation.

[0016] Furthermore, due to the aforementioned high contrast of the shadow image, a relatively simple evaluation algorithm with high processing speed can be used in the evaluation unit, which further promotes a high production speed on the production line. In addition, it has been found that, due to the relatively simple evaluation algorithm and / or the high sharpness of the shadow image, the evaluation unit can reliably determine whether the respective workpiece is in order or not and must be removed.

[0017] The described advantages are particularly evident when compared to inspection systems in which the image of the workpiece is generated in reflected light, for example by creating a mirror image of it, resulting in a high proportion of light diffusely emitted from the workpiece.

[0018] The workpiece can be, in particular, an injection-molded component. The workpiece can also be, for example, a container such as one used for analytical purposes and / or for carrying out chemical reactions on a microscale, without being limited to this, so that even relatively small workpieces can be tested very reliably.

[0019] Preferably, the optical system is configured to generate a shadow image of the workpiece with minimal distortion, preferably one that is at least substantially undistorted or undistorted, from at least one direction transverse to the workpiece's longitudinal axis, and / or to project the generated shadow image onto the detection device with minimal distortion, or preferably at least substantially undistorted or undistorted. Imaging errors of the workpiece, such as those that occur when using curved concave mirrors, are thus reduced or avoided. This increases the reliability of the workpiece inspection. The optical system of the inspection system according to the invention therefore preferably does not include curved concave mirrors, and particularly preferably does not include any optical elements with curved optical surfaces, such as curved reflective surfaces, except for the optics of the light source and / or the lens of the detection device.In principle, however, a certain, usually rough, inspection of the workpieces can also be carried out by generating distorted shadow images.

[0020] The lighting device can comprise multiple light sources, particularly when several workpieces or multiple rows of workpieces are to be inspected simultaneously using the inspection system. The workpiece to be inspected is preferably illuminated by exactly one light source to generate a shadow image of it. A single light source can optionally illuminate multiple workpieces, preferably simultaneously, particularly by using a beam splitter. Optionally, multiple light sources can illuminate a single workpiece, for example, from different directions, optionally also to generate multiple shadow images of the given workpiece from different directions, either simultaneously or at different times.The workpieces can be guided past the respective light source or several light sources using a movable holding device in order to check the respective workpiece using the shadow image.

[0021] The optical detection device can preferably be designed as a camera, but can also be designed in other suitable ways, such as an optical sensor, in particular an area sensor, or the like. A camera as a detection device has proven particularly effective, as it reliably captures the shadow image of the workpiece and enables simple image processing of the shadow image. Processing the camera image by a suitable evaluation unit is particularly easy. The detection device is preferably arranged in a stationary position relative to the optical system of the inspection device and / or to the light sources generating the respective shadow images during the acquisition of two or more shadow images of workpieces from different workpiece series.

[0022] Preferably, the inspection system comprises an evaluation unit that is connected to the optical detection device via signal transmission and by means of which any material defects can be identified and analyzed. In particular, the evaluation unit can compare the shadow image of the workpiece (generally: "shadow image") captured by the detection device with a reference image of a defect-free workpiece. A corresponding reference component can also be stored in the evaluation unit as a defect-free workpiece in order to perform the comparison and evaluation. It is understood that the comparison of the shadow image can also be performed with a data set corresponding to a defect-free workpiece. The evaluation can generally be carried out by an image processing method, a computational method, or in another suitable manner.

[0023] Preferably, the optical detection device and the signal-transmitting evaluation unit connected to it, which preferably evaluates the detected shadow images with a computing unit, are configured such that the workpiece's concentricity can be detected and / or calculated from this plurality of shadow images. Workpiece concentricity is understood to mean that one or more longitudinal sections, preferably encompassing the free end of the workpiece, are arranged in the workpiece's longitudinal axis at an angle to each other in directions that are each perpendicular to the workpiece's longitudinal axis. The two directions mentioned can, in particular, form an angle of 90° to each other.When the workpiece is rotated about its longitudinal axis, its position relative to its longitudinal axis remains unchanged when viewed from the free end along its longitudinal axis. Thus, the image of a round workpiece end, such as a round pipette tip opening, appears as a circle with the same diameter as the free end when the workpiece is rotated. The inspection system according to the invention is specifically designed to reliably detect such concentricity or deviations from it.

[0024] To generate an at least substantially undistorted or undistorted shadow image of the workpiece, the optical system preferably comprises one or more plane mirrors, which have proven particularly advantageous for enabling the desired reliable workpiece inspection and for generating a shadow image with minimal distortion or distortion, and / or for projecting this image undistorted onto the detection device. In general, within the scope of the invention, "undistorted" is also understood to mean, specifically, at least substantially distortion-free or, in particular, distortion-free. Such a plane mirror is preferably arranged in the beam path between the light source of the illumination device and the workpiece, wherein preferably several or all of the optical elements of the optical system between the light source and the workpiece consist of plane mirrors. The use of the plane mirror(s) results in an overall particularly distortion-free or undistorted image.Plane mirrors enable distortion-free image generation of the workpiece, particularly in the form of a shadow image, as optical aberrations are reduced or avoided. Furthermore, they are particularly cost-effective optical elements to manufacture, for example, compared to a complex lens system, and require very little installation space, which is especially advantageous when examining closely spaced workpieces.

[0025] Preferably, the optical system in the beam path between the light source and the workpiece has at least two or more plane mirrors arranged one behind the other in the beam path. Preferably, all of the optical elements between the light source and the workpiece are designed as plane mirrors, i.e., exclusively plane mirrors are provided. Preferably, and especially in combination with this, at least one or more or all of the optical elements between the workpiece and the optical detection device are designed as plane mirrors, i.e., exclusively plane mirrors are provided. Preferably, the optical element of the optical system arranged in the direction of the beam path directly in front of the workpiece and / or directly behind the workpiece is a plane mirror. This allows for a particularly low-distortion or practically distortion-free generation of a shadow image of the workpiece and / or a particularly low-distortion or...The optical detection device provides virtually distortion-free capture of the generated shadow image, thus enabling particularly reliable inspection of the workpiece.

[0026] Preferably, the optical system is designed such that the rays incident on the workpiece, which generate the shadow image of the workpiece, are a light beam consisting of rays that are at least substantially parallel or parallel to each other. Preferably, and particularly in combination with the feature mentioned above, the rays of the shadow image incident on the optical detection means are aligned at least substantially parallel or parallel to each other. This enables the generation of a shadow image of the workpiece with particularly low distortion or no distortion at all. The rays of the light beam incident on the workpiece can diverge or converge by ≤ ± 20°, preferably ≤ ± 10°, ≤ ± 5°, or ≤ ± 2° with respect to the direction of incidence of the light beam on the workpiece; they are particularly preferably parallel to each other.The cross-section of the light beam preferably captures the entire width or cross-section of the workpiece section to be examined.

[0027] It is particularly advantageous that the beam path between the illumination-side optical element located immediately upstream of the workpiece and / or the detection-side optical element located immediately downstream of the workpiece is aligned at least substantially perpendicular or perpendicular to the workpiece's longitudinal axis. This allows material defects and deviations from the target geometry in the area of ​​the workpiece's free end to be detected with exceptional reliability. The beam path between the illumination-side optical element and the workpiece and / or the beam path between the detection-side optical element and the workpiece, wherein the optical element is arranged directly on the workpiece with respect to the respective beam path, can form an angle of ≤ 20° or ≤ 15°, preferably ≤ 10° or ≤ 5°, and particularly preferably approximately 0°, to the perpendicular of the workpiece's longitudinal axis.The optical element located directly on the side of the illumination means and / or the detection means, which is therefore located closest to the workpiece in the beam path, is preferably a plane mirror.

[0028] Preferably, the beam path of the light emitted by the illumination device and detected by the optical detection means is telecentric on the object side and / or image side, particularly preferably on both sides. In particular, the optical detection means can have a telecentric lens. This enables the generation of a shadow image of the workpiece that is at least substantially undistorted or undistorted, and its detection by the detection means is at least substantially undistorted or undistorted, thus allowing for a particularly reliable verification of the defect-free condition of the workpiece under inspection. Generally, the light rays incident on the workpiece are preferably parallel rays. Generally, the light rays incident on the optical detection means are preferably parallel rays.

[0029] Preferably, the beam path includes at least one beam splitter which divides the light emitted by the light source of the lighting device into at least two separate partial beams and directs these at least two partial beams onto the workpiece, i.e., one and the same workpiece, to generate at least two shadow images of it. This allows a shadow image of the workpiece to be generated from several different directions, enabling particularly reliable detection of any workpiece defects, which may be visible to varying degrees when viewing the workpiece from different directions using the optical detection means. The beam splitter preferably has optically effective surfaces designed as plane mirrors, which effect the beam splitting. Preferably, all of the optically effective surfaces of the beam splitter are designed as plane mirrors.For example, the beam splitter can consist of two plane mirrors arranged at an angle to each other, with the vertex of the angle preferably positioned in the beam path. At the vertex of the angle, the two optical elements, in particular plane mirrors, of the beam splitter can converge at an edge. The angle enclosed between the two optical elements of the beam splitter can be less than 180° or less than 170°, in particular 145° to 30°, more preferably 120° to 60°, and in particular approximately 90°, but also, for example, 160° to 90°, wherein the enclosed angle is located on the side of the vertex facing away from the beam path. Furthermore, this provides a particularly cost-effective design for the inspection system, since, for example, separate lighting devices for generating a shadow image of the workpiece from a specific direction are avoided.Alternatively, a beam splitter can also be constructed, for example, by directing the light emitted by the lighting device onto a first optical element, preferably a plane mirror, which occupies an illuminated area F1. This area is preferably illuminated with at least substantially uniform luminance across its surface, and the light is then emitted from this surface onto at least two or more optical elements, each with an area F2, which are preferably each designed as a plane mirror. The area of ​​the light source, for example, also as a point source, can be at least the area F1. The area F1 is preferably larger than the area F2; more preferably, the area F1 is at least as large as the sum of the areas F2. The light emitted from the areas F2 is preferably directed onto the workpiece to generate shadow images of it.The number of generated shadow images can correspond to the number of provided surfaces F2. Surfaces F1 and F2 are each preferably flat surfaces, preferably each formed by a plane mirror.

[0030] Preferably, the beam path includes at least one beam splitter which divides the light emitted by the light source of the illumination device into at least two separate partial beams and directs these at least two partial beams onto different workpieces to generate at least two shadow images of the different workpieces. This reduces the complexity of the equipment and makes the system particularly suitable for examining closely spaced workpieces, i.e., those generally arranged close to each other on the fixture. For details regarding its design, please refer to the description of the beam splitter above.

[0031] Preferably, the partial beam paths of the inspection system are configured according to claim 8, as described generally for the beam path within the scope of the invention. The optical elements of at least two or all of the partial beam paths thus preferably comprise at least one or more plane mirrors; preferably, all of the optical elements of the respective partial beam path are plane mirrors, which is preferably configured accordingly for all of the partial beam paths generated by a lighting device. This enables a particularly low-distortion or at least substantially distortion-free generation and acquisition of the shadow image(s) of the respective workpiece.

[0032] By irradiating the workpiece with different partial beams from various directions, the resulting shadow images allow for the determination of the circularity of the examined workpiece area, particularly its free end, and can be calculated using a suitably configured evaluation device. The partial beams, directed at the workpiece and forming an angle with each other, are preferably arranged in a plane perpendicular to the workpiece's longitudinal axis.

[0033] Preferably, a light deflection device of the optical system is provided in the beam path between the light source and the workpiece in the plane where the light is radiated at least substantially perpendicular to the workpiece's longitudinal axis, i.e., preferably in a plane perpendicular to the workpiece's longitudinal axis. Here, (i) with respect to the direction of illumination of the light in the plane perpendicular to the workpiece's longitudinal axis towards the workpiece and / or (ii) with respect to the direction of movement of the holding device by the optical system, at least a first part of the light deflection device is arranged in front of the workpiece and a second part of the light deflection device is arranged behind the workpiece, with respect to the aforementioned direction of illumination or direction of movement of the holding device, wherein the two parts of the light deflection device each produce a shadow image of the workpiece.The irradiation direction of the workpiece is preferably the direction in which the light, which is coupled directly into or deflected in the plane perpendicular to the longitudinal axis of the workpiece, shines towards the workpiece. Preferably, therefore, in the direction of the beam path from the illumination device to the detection means, a light deflection device of the optical system is provided in the beam path upstream of the workpiece, which is arranged in a plane perpendicular to the longitudinal axis of the workpiece. In this device, at least a first part of the light deflection device is arranged in front of the workpiece and a second part of the light deflection device is arranged behind the workpiece, in the direction of light radiation towards the workpiece or in the movement direction of the holding device. The first and second parts of the light deflection device described above can each be arranged directly in front of the workpiece with respect to the beam path.The light deflection device, positioned in front of and behind the workpiece with respect to the direction of incidence, directs light beams onto the workpiece in different directions to create shadow images. These light beams form an angle with each other. This angle can be, for example, 145° to 35°, preferably 60° to 120°, and particularly preferably approximately 90°, without being limited to these values. This creates shadow images of the workpiece from different perspectives and enables inspection of the workpiece over a larger area. Preferably, the light from the aforementioned deflection devices, positioned in front of and behind the workpiece, is directed towards the workpiece in a direction perpendicular to the workpiece's longitudinal axis.In particular, the workpiece's concentricity can be determined from the shadow images of the various views, for example, by calculating them using the evaluation unit. In this embodiment of the inspection system's optical system, at least one part, several parts, or all parts of the light deflection device, which is arranged in front of and / or behind the workpiece with respect to the direction of the beam path, are preferably designed as a plane mirror. This enables a particularly low-distortion or at least substantially distortion-free image of the workpiece. The part of the light deflection device designed as a plane mirror is preferably arranged directly in front of or behind the workpiece with respect to the beam path.Preferably, two or more parts of the light deflection device, preferably in the form of plane mirrors, are arranged in front of the workpiece in the direction of the beam path, and two or more parts of the light deflection device, preferably in the form of plane mirrors, are arranged behind the workpiece in the direction of the beam path, in a plane. This plane is preferably arranged at least substantially perpendicular to the longitudinal axis of the workpiece; this plane can, for example, be set at an angle of ≤ 25° or ≤ 15°, particularly preferably ≤ 5°, to the longitudinal axis of the workpiece. Preferably, this plane is arranged perpendicular to the longitudinal axis of the workpiece.This results in a particularly advantageous arrangement of the optical elements of the optical system, enabling both the generation of a distortion-free shadow image of the workpiece and a particularly compact design suitable for use in an inspection system for checking a large number of workpieces on a holding device. The plane of the optical elements can, in particular, be arranged at least substantially parallel or parallel to the main plane of a holding plate of the holding device, with the workpieces being held on this plate during inspection.

[0034] The lighting device and / or the optical detection means are preferably arranged outside the plane of optical elements that direct the illumination light directly onto the workpiece to generate a shadow image, or are arranged directly behind the workpiece in the direction of the beam path and deflect or project the shadow image towards the optical detection means. Light deflection devices are preferably arranged between the lighting device and / or the detection means, each of which, independently of one another or in combination with one another, is designed as a plane mirror, thus providing distortion-free optics for examining the workpiece.

[0035] Generally of independent importance, preferably generally within the scope of the invention, at least a portion of the optical elements arranged in front of the workpiece in the direction of the beam path is preferably designed as a beam splitter, which divides the light beam of the illumination device into at least two partial beams, wherein, by means of the beam splitter, a first partial beam is deflected or directed towards a first workpiece and a second partial beam is directed towards a second workpiece. The beam splitter is preferably an optical element that directs the illumination light directly onto the workpiece to generate a shadow image of the workpiece. The first and / or the second partial beam can be directed directly onto the respective workpiece to generate a shadow image of it.The two partial beams preferably lie in a plane corresponding to the plane of the optical elements described above, which is arranged at least substantially perpendicular or perpendicular to the longitudinal axis of the workpiece. The beam splitter is preferably the optical element located in front of the respective workpiece in the direction of the beam path. The beam splitter is particularly preferably a part of the light deflection device described above, especially a part of the optical system located in front of the workpiece in the direction of illumination and / or in the direction of movement of the workpiece holding device through the optical system, wherein the beam splitter is preferably located directly in front of the workpiece in said beam path direction and / or direction of movement.Thanks to the instrumental advantages of the beam splitter, the optical system is also particularly simple in its construction, requiring less effort to adjust the optical elements and resulting in fewer possible optical imaging errors, due to the multiple functions of the beam splitter.

[0036] Preferably, the workpieces are arranged in several laterally spaced rows on the holding device. The at least two partial beams generated by the beam splitter, which are directed onto the workpiece to create a shadow image, can be directed onto at least two workpieces in the same row or onto workpieces in different rows of the workpiece arrangement. Particularly preferably, the beam splitter generates exactly two partial beams, which are directed onto exactly two different workpieces.

[0037] Preferably, the beam splitter is formed by two or optionally more plane mirrors, which are angled relative to each other, preferably at an angle of ≥ 20° and / or ≤ 145°, more preferably at an angle of ≥ 30°, more preferably ≤ 90° or ≤ 60°, and particularly preferably at approximately 45° or approximately 120°. The beam-dividing optical surfaces of the beam splitter are preferably each designed as a plane mirror, wherein the optical surfaces can meet at an edge, which preferably faces the illumination device. The beam splitter can be arranged symmetrically in the beam path, so that the incident illumination is divided into two partial beams of equal illuminance. The direction of incidence of the illumination on the beam splitter is preferably aligned with the bisector of the angle between the mutually angled optical surfaces of the beam splitter.The beam splitter can optionally generate more than two partial beams, preferably with the same illuminance or light intensity.

[0038] Preferably, the optical system in the beam path upstream of the workpiece comprises a plurality of mirrors distributed around the circumference of the workpiece, each producing a shadow image of the workpiece. These mirrors are preferably designed as plane mirrors, preferably all of the mirrors producing a shadow image of the workpiece. The mirrors producing a shadow image of the workpiece are preferably arranged in the beam path direction directly in front of the workpiece, so that the light redirected by the mirrors or projected directly onto the workpiece produces the respective shadow image. The mirrors are preferably spaced apart from one another in the circumferential direction of the workpiece, which is preferably perpendicular to the longitudinal axis of the workpiece, such that each mirror produces a shadow image that is spaced apart from an adjacent shadow image in the circumferential direction of the workpiece.The individual shadow images produced by the mirrors are thus separated from each other in the direction of the workpiece's circumference. However, the circumference areas of the workpiece depicted in the adjacent shadow images can overlap. Each of these shadow images is then deflected or projected onto the optical detection device by light deflection devices arranged behind the workpiece in the direction of the light path. This allows the detection device to receive multiple separate shadow images of the respective workpiece, with each shadow image corresponding to a section of the workpiece's circumference. This enables a detailed inspection of the workpiece's circumference with high precision.It is understood that the mirrors can be arranged in the circumferential direction of the workpiece such that the shadow images, preferably those projected and captured adjacent to the detection device, depict overlapping circumferential areas of the workpiece. This allows a continuous circumferential area of ​​the workpiece to be depicted on the detection device using multiple shadow images, enabling particularly precise inspection of the workpiece. The majority of mirrors can be arranged along an arc, e.g., a circular segment, around the workpiece, wherein the arc or circular segment extends, for example, over ≥ 60° or ≥ 90°, preferably ≥ 120° or ≥ 145°, or up to approximately 180° or possibly more around the workpiece, in order to depict a large circumferential area of ​​the workpiece on the detection device using multiple shadow images.Except for the workpiece's path as it moves through the optical system, the mirrors can be arranged approximately in a semicircle around the workpiece, but also in other configurations. Two, three, four, or more mirrors, for example five, six, or more, particularly plane mirrors, can be used to direct light onto the workpiece and create shadow images.

[0039] Preferably, the optical system in the beam path between the workpiece and the optical detection device comprises a plurality of mirrors, preferably plane mirrors, which are arranged distributed around the circumference of the workpiece. At least one or more of these mirrors, preferably exactly one, are assigned to each of the plurality of mirrors that generate a shadow image and transmit the shadow image generated by the respective mirror arranged in front of the workpiece in the beam path direction to the detection device. This allows the detection device to capture several, preferably several separate, shadow images. The mirrors that generate a shadow image and the mirrors located downstream of the workpiece in the beam path each preferably partially surround the workpiece, such that preferably at least two or more mirrors are provided in each case, distributed around the circumference of the workpiece, each preferably in the form of plane mirrors.

[0040] Preferably, a (first) plane mirror is provided on the illumination side, i.e., between the lighting device and the workpiece. This mirror directs or deflects the light emitted by the light source assigned to the workpiece for shadow image generation, preferably directly onto several mirrors, preferably plane mirrors, arranged distributed around the circumference of the workpiece. These mirrors are preferably positioned in the direction of the beam path directly in front of the workpiece and generate a shadow image of the workpiece. This results in a particularly simple design of the optical system of the inspection system, which, due to the arrangement of plane mirrors, provides low-distortion or...The system produces a substantially distortion-free image of the workpiece, and, due to the multiple mirrors arranged directly in front of the workpiece, each producing the same shadow image, a relatively large circumference of the workpiece can be inspected. Furthermore, the (first) plane mirror, arranged on the illumination side, can produce multiple shadow images of the workpiece, preferably using only one light source. For this purpose, the illumination device illuminates an area F1 of the first plane mirror, which is equal to or larger than the sum of the illumination areas of the multiple mirrors arranged directly around the workpiece, so that multiple shadow images can be produced by just one illumination device.The multiple (second) mirrors that generate a shadow image of the workpiece can be arranged in a plane that is at least substantially perpendicular or perpendicular to the workpiece's longitudinal axis. The first plane mirror can be arranged outside this plane of the second mirrors. Alternatively or additionally, a plane mirror is provided on the detection device side facing the workpiece. This plane mirror projects the shadow images of several or all of the mirrors distributed around the circumference of the workpiece—each preferably receiving a shadow image directly from the workpiece—toward the detection device. The multiple mirrors are preferably arranged directly behind the workpiece in the direction of the beam path. Each of these multiple mirrors thus reflects a shadow image of the workpiece toward the plane mirror.The plane mirror thus preferably captures several or all of these shadow images from the plurality of mirrors simultaneously and projects them, preferably simultaneously, towards the detection device. This is advantageous in order to achieve a projection of the shadow images towards the detection device with as little distortion as possible or without any distortion at all.

[0041] In general, within the scope of the invention, the aforementioned mirrors, beam splitters, and / or light deflection devices are preferably arranged in a fixed position relative to one another during the inspection process of the respective workpiece. This naturally includes the fact that the optical elements are preferably adjustable at their respective positions in the beam path.

[0042] According to a first embodiment (i), the inspection system is designed such that the holding device has at least two spaced-apart rows of holders, each for at least one or exactly one workpiece. A light deflection device is provided between the workpiece and the optical detection means, which generates a shadow image of at least two workpieces from different rows and directs it onto the optical detection means, i.e., onto one and the same detection means. The detection means, which here captures the shadow images of workpieces from several rows, is preferably a structural and / or functional unit, such as preferably exactly one camera or exactly one sensor. The detection means preferably has exactly one lens into which the shadow images of the two or more different shadow images from different rows of workpieces fall.This design results in a particularly simple inspection system, enabling the inspection of multiple workpieces with minimal equipment, preferably simultaneously. Only one detection device is required to inspect workpieces from several rows. This also makes the inspection system cost-effective to manufacture, as the detection device, such as a camera, incurs significant costs. Furthermore, this design is particularly compact, allowing for reliable inspection even when numerous workpieces are closely spaced on the holding device.

[0043] Preferably, the detection device is designed to simultaneously capture the shadow images of workpieces from different rows. Preferably, the optical system, together with the workpiece arrangement within it and the detection device, are designed such that multiple shadow images can be projected onto the detection device and simultaneously captured, which is particularly relevant for workpieces from different workpiece rows.

[0044] The light deflection device is preferably arranged between the rows of workpieces, preferably between adjacent rows of workpieces, and particularly preferably at half the distance between the respective rows of workpieces. The light deflection device can be arranged at the level of the workpieces when viewed perpendicular to the longitudinal axis of the workpieces. The same applies to a beam splitter, which can also be designed as a light deflection device.

[0045] In general, within the scope of the invention, the workpiece holding device is positionally variable relative to the optical system of the inspection system. Preferably, the optical system, and particularly preferably all its components, are arranged in a stationary position, and the holding device is designed to be positionally variable, in particular with translational positional change, especially with a linear movement. The holding device, and thus also the rows of workpieces arranged on it, can therefore be moved past the optical system or the deflection device mentioned above, relative to the optical system and / or the aforementioned light deflection device and / or beam splitter between the rows of workpieces.This allows the holding device to be part of a workpiece transport system that moves the workpieces from the workpiece forming device, such as an injection molding machine, past the inspection system and into other components of a workpiece production line, such as a handling device for removing defective workpieces, a packaging machine, or the like. The transport system can extend continuously along the entire length of the production line. The inspection system is therefore preferably part of an automated workpiece manufacturing and / or packaging line.The individual devices are preferably part of a continuous workpiece production line, wherein the workpieces, preferably arranged on a holding device and / or a carrier, are transferred directly, preferably without intermediate storage in a separate intermediate storage area, from one device to the next within the production line.

[0046] According to another embodiment (ii), the inspection system is designed such that the holding device has at least two spaced-apart rows of holders, each for at least one or exactly one workpiece, wherein a beam splitter is provided between the lighting device or light source and the workpiece, which divides the illumination light and preferably simultaneously directs it onto workpieces of different rows. This embodiment is particularly advantageous in combination with the inspection system according to the first embodiment (i) of claim 1 and its further developments. This significantly reduces the number of light sources required for inspecting workpieces of several rows. Thus, for example, at least two or optionally even more rows of workpieces can be inspected using only one light source with the inspection system according to the invention.The light source for the various workpiece series is preferably a single structural and / or functional unit. The light source can comprise exactly one light source. The light source preferably comprises exactly one optic or lens, which preferably generates exactly one light beam. The light source is preferably arranged in a stationary position relative to the optical system of the inspection device and / or to the detection device(s) that capture the respective shadow images during the irradiation of two or more workpieces from different workpiece series.

[0047] The beam path divider is preferably arranged at the level of the workpieces, perpendicular to the workpiece's longitudinal axis when viewed from above, so that when the holding device changes position relative to the inspection system, the workpieces or rows of workpieces are guided laterally past the beam path divider. This also results in a particularly compact design for the inspection system.

[0048] If the holding device has at least two or more spaced-apart rows of holders, each for at least one or exactly one workpiece, then the detection means and / or at least one light deflection device, which directs light from the lighting device or from a light source to different rows of workpieces, and / or a light deflection device, which deflects light from the workpiece or the workpiece shadow image towards the detection means, is preferably arranged between the rows of workpieces, preferably centrally between said rows of workpieces. This results in a compact and structurally particularly simple and compact design of the optical system or the inspection system as a whole.At least two spaced-apart, preferably adjacent, rows of workpieces can thus be inspected using only one light source and / or only one detection device, which also reduces the equipment required. The same applies to a preferred arrangement of a beam splitter, which divides the beam path from a light source and directs or projects the at least two partial beams onto different rows of workpieces.

[0049] Preferably, the light source of the lighting device is a point source. The point source preferably has a uniform light-emitting aperture extending over a continuous surface, which emits the light from the light source towards the optical system. The lighting device preferably has a constant luminous intensity across the entire area of ​​the point source. This includes the fact that the area of ​​the point source is preferably at least equal to or greater than the workpiece diameter at the longitudinal section of the workpiece being inspected by the inspection system. It is further preferred that the point source has a light-emitting surface whose width or diameter corresponds to the spacing of the workpiece rows, with the different workpiece rows being illuminated by one and the same lighting device to generate shadow images of the respective workpiece.The spacing between the workpiece rows also includes the width of the workpieces on the side opposite each adjacent workpiece row. These workpiece rows are preferably arranged adjacent to one another. These workpiece rows are preferably straight. It is generally understood that the holders of the holding device are each equipped with at least one or exactly one workpiece during inspection of the workpieces by means of the inspection system. This point source is to be distinguished in particular from an annular light source whose central region does not emit light in the direction of the one or more workpieces to be inspected.

[0050] According to a first, generally preferred embodiment of the invention, the optical axis of the light source assigned to the respective workpiece and / or the optical axis of the detection means, preferably both optical axes, are aligned parallel to the longitudinal axis of the workpiece. This allows for a structurally simple arrangement of the lighting device and / or detection means and makes it easy to generate a shadow image of the respective workpiece. Furthermore, this allows for easy adjustment of the optical system. For the simultaneous inspection of several workpieces held on the fixture, the light sources and detection means for inspecting multiple workpieces can be easily arranged in a common housing, for example, side by side.Preferably, the housing includes all light sources and detection means which are to be arranged for the inspection of the workpieces on a holding device, preferably in several rows next to each other.

[0051] According to a second, generally preferred embodiment of the invention, the light source and detection means associated with the respective workpiece can be arranged such that the beam path from the light source to the workpiece and, on the other hand, from the workpiece to the detection means, are coaxially aligned at least over a portion of the beam path. The light source and detection means can be spatially aligned relative to each other such that the light emitted directly from the lighting device is arranged at least approximately perpendicular or perpendicular to the light beam entering the detection means. This results in a particularly compact design for certain applications.

[0052] According to the first and second variants, the descriptions can apply to all light sources and / or detection means of the inspection system. Generally, within the scope of the invention, a light source "assigned to the workpiece" is understood to be one that produces a shadow image of the respective workpiece.

[0053] Preferably, the optical system comprises an optical element that is partially transparent and is positioned both in the beam path of the light emitted from the illumination device towards the workpiece and simultaneously in the beam path of the light directed from the workpiece towards the detection means. This optical element is preferably designed as a plane mirror. The optical element, and thus the light beam, is preferably oriented obliquely to the beam path of the light incident from the illumination device and obliquely to the direction of the light beam directed from the workpiece towards the detection means, preferably at an angle of approximately 45° to each light beam. The optical element therefore exhibits reflective properties with respect to the illumination light and transparent properties with respect to the light directed towards the detection means.The optical element in question can, for example, have a suitable coating, such as is common on semi-transparent mirrors. The light incident on this optical element from the illumination side and the light passing through to the detection element can fall on the same area of ​​the optical element. This allows for a flexible arrangement of the lighting system relative to the research equipment, which is also compact and space-saving.

[0054] In a preferred embodiment, the optical system is designed to illuminate the workpiece to be examined, preferably simultaneously, with at least two separate partial beams from at least one, preferably exactly one, light source, in order to generate a different shadow image of the respective workpiece with each partial beam. If the separate partial beams between the workpiece in its examination position and the detection means, which is preferably the same detection means such as a camera or a sensor for the at least two partial beams, have different beam path lengths, then an optical element is preferably arranged in at least one of the beam paths of the partial beams between the workpiece and the detection means, which adjusts the image sharpness of the different shadow images in the detection means to each other. This optical element is referred to here as the "adjustment element".The beam path length of the partial beam paths can optionally be considered their geometric length. Due to the given depth of field of the optics or the lens of the detection device, in particular a given focal length thereof, the problem arises that objects at different distances from the detection device can appear differently sharp. Preferably, the lens is focused sharply on the workpiece with respect to one partial beam path, so that the shadow images of that workpiece produced by other partial beams may appear blurry. The at least one optical adjustment element in the partial beam paths thus adjusts the sharpness of the different shadow images to each other, so that preferably all shadow images are sharp, regardless of the beam path length of the respective partial beam path.The images appear equally sharp, thus enabling the reliable inspection of workpieces from different batches. Furthermore, this allows shadow images of the given workpiece to be generated from different directions, and the optical system and / or light source and / or detection means to be adapted in various ways to specific requirements such as workpiece geometry, spatial conditions at the inspection system, or the like. Preferably, the optical adaptation element is arranged in a partial beam path that has a longer or the longest beam path of the various partial beams generating shadow images of the single workpiece. Preferably, such an optical element is omitted in the partial beam path with the shortest beam path.

[0055] The matching element is preferably designed as a light-refracting optical element, such as one or more prisms, one or more plano-optical elements like planar plates with planar, parallel light-entry and light-emission surfaces, or combinations thereof. The partial rays preferably fall perpendicularly onto an optical surface of the optical element, such as its light-entry surface. The partial rays preferably exit the optical element perpendicularly to its optical exit surface. The partial rays preferably strike the optical matching element as bundles of parallel light rays. The partial rays are preferably emitted or deflected by the matching element as bundles of parallel light rays towards the detection means. In a preferred embodiment, the matching element is designed as a 60°–120° prism, preferably as a 90° prism.One or more adaptation elements, particularly prisms, can be arranged directly in front of an optical deflection element, preferably a deflection mirror, of the optical system. The deflection element is preferably arranged at an angle to the workpiece's longitudinal axis in its inspection position to deflect the beam path from a plane at least substantially perpendicular to the workpiece's longitudinal axis and direct it to the detection element, which is preferably located outside this plane. This results in a particularly compact design. The at least one adaptation element and the deflection element, particularly a plane mirror, can be designed as a single unit, which simplifies the assembly and adjustment of the optical system.The adaptation element can also extend only over a first part of the optical surface of the deflecting element, whereby at least one other partial beam, which represents a different shadow image of the one said workpiece, falls on the other, i.e., second, part of the optical surface of the deflecting element and is deflected from it to the same detection means.

[0056] Optionally, the matching element can also include at least one or more mirrors, for example, flat mirrors, which can also be arranged directly one behind the other in the direction of the beam path. However, the design of the matching element as a light-refracting optical element is preferred due to its particularly compact construction.

[0057] In general, the optical system preferably does not include any optical elements with convex or concave curved optical surfaces, such as lenses and / or concave mirrors with curved reflective surfaces. Preferably, the optical system does not include any diffracting optical elements. Any objective lens of the respective detection device and / or any objective lens of the respective light source are generally not considered part of the optical system.

[0058] In one embodiment, preferably all optical elements of the optical system are plane mirrors, except for any optical elements for adjusting the image sharpness of the shadow images, in particular those for adjusting the image sharpness of different shadow images of the same workpiece with different partial beams with different path lengths.

[0059] All optical elements of the optical system are preferably arranged in a fixed position relative to the lighting device or light source and / or the detection device.

[0060] In general, within the scope of the invention, the inspection system can be designed to inspect several longitudinally spaced sections of the workpiece. For example, the workpiece can pass through two independent inspection systems arranged one behind the other in the transport direction of the holding device, each inspecting different sections of the workpiece. Given a known transport speed of the holding device, the shadow images generated in the two inspection systems can each be assigned to a specific workpiece, allowing for a more precise inspection of its geometry or material defects. By detecting two different longitudinally spaced inspected sections, the workpiece's concentricity can also be determined or calculated using the evaluation unit.If necessary, the two inspection systems for inspecting different sections spaced apart in the longitudinal direction of the workpiece can also be combined in one station, for which, for example, a separate lighting device can be provided for each area to be inspected in the longitudinal direction of the workpiece, whereby the optical system can be designed in such a way that the shadow images of the two workpiece sections spaced apart in the longitudinal direction of the workpiece are captured by means of the same detection means.

[0061] The invention further comprises an inspection method for checking elongated workpieces using an inspection system according to the invention. Descriptions of the inspection method also apply accordingly to the inspection system and vice versa.

[0062] In a preferred embodiment of the inspection method, the holding device for at least one or a plurality of workpieces to be inspected is moved relative to the optical system in order to transfer each workpiece from a non-inspection position to an inspection position at the optical system that generates the shadow image of the workpiece. The exposure time of the workpiece for generating its at least one shadow image is less than or equal to 1 millisecond, preferably ≤ 250 microseconds, ≤ 100 microseconds, or ≤ 50 microseconds. This is made possible by the high contrast of the workpiece image in the form of a shadow image. The light source for illuminating the workpiece can be operated intermittently, i.e., pulsed, or continuously. In general, in electronic image acquisition and processing, the exposure time can be the duration within which shadow images or...Relevant image information is accumulated to generate the shadow image to be evaluated. The exposure time can correspond to or be shorter than the duration of the workpiece in its examination position. The transport speed of the workpiece or the holder through the optical system can be ≥ 50 mm / sec, ≥ 100 mm / sec, or ≥ 250 mm / sec, and optionally ≥ 500 mm / sec.

[0063] The invention is explained below by way of example with reference to several embodiments. It is understood that various features of the respective embodiment can also be combined with features of other embodiments. All features of the embodiments are disclosed independently and generally within the scope of the invention. Identical components or features are provided in the figures with the same reference numerals or with reference numerals increased by "10" or a multiple thereof. The figures show: Fig. 1: a perspective view of a holding device of an inspection system according to the invention; Fig. 2: A perspective view of the optical system of a first inspection system according to the invention, comprising lighting devices, the optical system, and an optical detection means with workpieces in a perspective view ( Fig. 2A) and in top view ( Fig. 2B) and in a modified embodiment ( Fig. 2C); Fig. 3: a second embodiment of the inspection system according to the invention with lighting device, detection means and optical system with several rows of workpieces; Fig. 4: A third embodiment of the inspection system according to the invention with a lighting device, detection means and an optical system with several optical elements arranged distributed around the workpiece, as well as with workpieces ( Fig. 4a), and with a simplified schematic representation of the beam path ( Fig. 4b); Fig. 5: a representation of the inspection system according to Fig. 4a and Fig. 4b with several optical systems and detection devices arranged side by side for the inspection of several rows of workpieces; Fig. 6: a representation of the data collected by a detection device of the inspection system according to Fig. 4a and Fig. 4b captured several shadow images of a workpiece; Fig. 7: another alternative inspection system with an optical system with a partially transparent optical element, Fig. 8: Schematic representations of the beam path of an inspection system according to the invention with beam path splitter or light deflection device according to a first embodiment ( Fig. 8a) and a second embodiment ( Fig. 8b).

[0064] The Fig. Figures 1 to 5 and 7, 8 show exemplary embodiments of the inspection systems according to the invention or parts thereof. Fig. 2, Fig. 3, Fig. 4, and Fig. Figure 7 shows inspection systems with an arrangement of several workpieces arranged in rows on the holding device. The holding device is either not shown or only schematically indicated; for example, a holding device according to Fig. 1 or another suitable holding device must be used.

[0065] Fig. Figure 1 shows a perspective view of a holding device 3 for an inspection system 1 according to the invention, wherein this holding device 3 can be provided in all embodiments of the inspection system 1 or generally within the scope of the invention.

[0066] The holding device 3 has a plurality of holders 3a, wherein at least one, or in particular exactly one, workpiece 2 is or can be held on each of the holders 3a. The workpiece 2 can, for example, be held on the respective holder 3a by vacuum, by a mechanical device, or in another suitable manner. The plurality of workpieces are fixed on the holder in a defined spatial position relative to one another, for which purpose the workpieces 2 are aligned with their longitudinal axes 2a ( Fig. 2a) are arranged coaxially to each other. The workpieces 2 are spaced apart from each other on the holding device 3, specifically in the longitudinal direction of the holding device or in the longitudinal direction of the rows R and transversely to this direction. The arrangement of the workpieces 2 on the holding device 3 can correspond to the arrangement of the workpieces as they are found in a forming device such as an injection molding machine with a plurality of cavities for the simultaneous production of injection-molded parts. The holding device 3 is separate from the other components of the inspection system, such as, in particular, a lighting device 4, an optical system 5, and an optical detection device 6 (see, e.g., Fig. 2) positionally variable, so that the workpieces arranged on the holding device 3 are transported by the optical system 5 by changing the position of the holding device, in particular in a translational movement, specifically a linear translational movement (direction of arrow), in order to be able to inspect the workpieces 2 for defects using the optical detection means 6, such as a camera. The holders 3a are arranged on a flat holding plate 3b. It is understood that the holding device can generally be designed in other ways, in particular that the multiple workpieces 2 can be arranged on the holding device in a different spatial arrangement relative to each other. The rows orThe workpieces are arranged in a straight line and parallel to each other; however, this is not strictly necessary. For example, the workpieces 2 can also be arranged in a pattern on the holding device, preferably corresponding to the design of the mold or the injection molding cavity of an injection molding machine. On the holding device 3 in . Fig. Figure 1 shows eight rows, each holding eight workpieces, without this being the only possible configuration. The holding device 3 is transported in its longitudinal direction, as indicated by the arrow, by the inspection system according to the invention, which can be part of an automated production system, and thus also moved in its longitudinal direction by the optical system of the inspection system. This can, of course, also occur in a direction transverse to the longitudinal extent of the holding device. The transport speed of the holder 3 by the optical system of the inspection system can be in the range of 250 mm to 1000 mm / sec or more.

[0067] Fig. Figure 2 shows a first embodiment of an inspection system 1 according to the invention for checking elongated workpieces 2, in particular injection-molded parts.

[0068] The inspection system 1 has a holding device 3 for holding at least one or a plurality of workpieces to be inspected, wherein the holding device is configured according to Fig. 1. The workpieces can be formed in several rows R separated from each other by a distance d (see Fig. 1) be arranged, the rows being preferably straight as shown here, but generally also in another arrangement.

[0069] The inspection system 1 comprises a lighting device 4 with at least one light source 4a. If several rows of workpieces are provided, several light sources may also be provided to emit light onto the workpieces for inspection; these light sources may be of identical design. The light source is designed here as a point source, but may also be designed in another way, whereby the respective light source can have a constant luminous intensity across its entire light-emitting surface. The diameter of the light source 4a is dimensioned such that it illuminates the optical elements of the optical system 5 described below sufficiently and preferably with uniform luminous intensity across their relevant area for workpiece inspection.According to the exemplary embodiment, the lighting device 4 comprises several light sources 4a, which are arranged side by side here, but can also have a different spatial arrangement or spacing from one another. Due to the special design of the optical system 5, as described below, the number of light sources 4a is less than the number of workpiece rows on the holding device 3. More precisely, the light sources 4a are arranged at half the distance between the workpiece rows R, preferably between adjacent rows that have a larger distance d than other adjacent rows. On each of the rows that define the area of ​​workpieces, another light source 4a is provided on the side facing away from the workpiece area. For a total of eight workpiece rows R on a holding device 3 according to... Fig. Thus, five light sources 4a are provided. It is understood that, depending on the embodiment of the inspection system according to the invention, each row of workpieces may also be assigned a separate light source 4a. Furthermore, it is understood that the inspection system can also be used to inspect only a single workpiece or only two or more workpieces arranged side by side.

[0070] Furthermore, the inspection system 1 comprises an optical system 5 for directing the light emitted by the light source 4a preferably laterally onto the workpiece 2 to be inspected, which is arranged on the holding device 3. As is generally the case within the scope of the invention, the emitted light is preferably in the visible range (380-780 nm), without being limited thereto. The workpiece 2 to be inspected is thus located in its inspection or measurement position on the inspection device, as shown in Fig. 2 and the other figures apply to the workpiece captured by the depicted beam path.

[0071] The light emitted from the respective light source 4a onto the workpiece 2 under inspection falls at an angle of 45° to 135°, preferably 60° to 120° or 75° to 105°, or, according to the exemplary embodiment, at an angle of 90° onto the longitudinal axis 2a of the workpiece, in order to be able to check the absence of defects in the workpiece 2. The optical system 5 directs the light from the light source 4a substantially or exactly perpendicular to the longitudinal axis 2a of the workpiece onto the workpiece.

[0072] The optical system 5 is designed such that it uses the workpiece 2 to generate its shadow image 73 ( Fig. 6) is irradiated and the shadow image is projected onto the detection device. The light rays incident on the workpiece are aligned at least substantially parallel or parallel to each other. The light source 4a, or all light sources of the lighting device 4, emit light beams with at least substantially parallel or parallel light rays. The optical system 5 is configured such that the light rays of the workpiece shadow image strike the optical detection device 6 as a bundle of at least substantially parallel or parallel light rays. The optical system 5 is preferably configured such that the generated shadow image is at least substantially undistorted or undistorted and that the shadow image falls onto the detection device at least substantially undistorted or undistorted. The exposure time of the workpiece can be less than 10 microseconds.

[0073] Furthermore, an optical detection device 6 (generally also referred to as "detection device") is provided, wherein the workpiece 2 is arranged in the beam path S of the light emitted by the light source between the light source 4a and the optical detection device 6, and the optical detection device captures the image of the workpiece 2 generated by the illumination. The detection device 6 is designed here as a camera, but can also be designed as an image sensor or in another suitable manner, with cameras being particularly preferred in order to capture the respective shadow image without distortion and subsequently to process it.

[0074] Preferably, an evaluation unit 7 is also provided, which is connected to the optical detection device 6 via signal transmission. The evaluation unit 7 is configured to enable or perform a comparison of the workpiece image captured by the optical detection device with a reference, for example, a reference component. The corresponding evaluation can be carried out using a computing device, for example, by superimposing or comparing the captured workpiece image with the reference. The evaluation using the evaluation unit can be computer-aided, for example, using electronic image processing, or carried out in another suitable way. In the simplest case, the workpiece image is displayed on a screen of the optical detection device for inspection by a person.

[0075] The optical system 5 is preferably configured such that it generates an undistorted shadow image of the workpiece 2 from at least one direction transverse to the workpiece's longitudinal axis and projects the generated shadow image undistorted onto the optical detection means. "Undistorted," also called "distortion-free," here and generally within the scope of the invention includes at least substantially distortion-free or distortion-free. The generation of the undistorted shadow image allows for a particularly reliable and simple method of checking the workpiece for defects.

[0076] The optical system 5 includes at least one plane mirror 5a, which directs the light from the light source 4a, or more generally, the light from the light source 4a assigned to the respective workpiece, onto the workpiece 2. Here, two such plane mirrors 5a and 5b are used to produce shadow images of the workpiece that are as undistorted as possible. With respect to the beam path from the light source 4a to the workpiece 2, the at least one plane mirror 5a, or here both plane mirrors 5a and 5b, is positioned directly in front of the workpiece. It is understood that, if necessary, more than two such plane mirrors, which direct light directly onto the workpiece, may be provided to produce shadow images of it. The resulting shadow image is at least substantially undistorted or undistorted compared to the workpiece.The light emitted by the plane mirrors 5a, 5b onto the workpiece 2 is redirected or projected in the direction of the beam path behind the workpiece at least essentially undistorted or undistorted onto the detection means 6 and is detected by it in each case.

[0077] In addition to at least one plane mirror 5a, 5b, or, according to the exemplary embodiment, at least two or more plane mirrors 5a, 5b, a deflecting mirror 5u, also designed as a plane mirror, is provided in the beam path on the illumination side, i.e., facing the workpiece in the beam path of the illumination device. One of the plane mirrors 5a, 5b can also be designed as a beam path splitter, as described below. The deflecting mirror 5u directs the light from the light source 4a towards the workpiece, with the light emission direction of the light source 4a being arranged at an angle to the light that falls on the workpiece to generate the shadow image. The light for generating the shadow image is directed onto the workpiece by means of the deflecting mirror 5u substantially or exactly perpendicular to the workpiece's longitudinal axis 2a.The light source 4a emits light at an angle other than at least substantially perpendicular to the workpiece's longitudinal axis 2a, here coaxial to the workpiece's longitudinal axis, in the direction of the workpiece 2. The deflecting mirror 5u thus deflects the light emitted by the light source 4a generally into a plane that is arranged at least substantially perpendicular or perpendicular to the tool's longitudinal axis 2a. The light deflection here is by 90°, and the deflecting mirror 5u is arranged at an angle of 45° to the workpiece's longitudinal axis 2a. By arranging at least one or more plane mirrors, which are positioned directly in front of the workpiece, here the plane mirrors 5a, 5b, and the deflecting mirror 5u, which is also designed as a plane mirror, a distortion-free shadow image of the workpiece is produced. The optical system 5 in the beam path between the lighting device and the workpiece 2 consists exclusively of plane mirrors.

[0078] Furthermore, the optical system 5 also includes at least one or more plane mirrors in the beam path between the workpiece 2 and the optical detection device 6, which are arranged one behind the other in the direction of the beam path; according to the exemplary embodiment, exclusively plane mirrors. The feature of "optical elements arranged one behind the other in the beam path" refers here and generally within the scope of the invention to the direction of propagation of the light.

[0079] The beam path S is telecentric on the objective side and / or image side. The illumination device thus has a telecentric light source, which emits light onto the workpiece with parallel rays. Several or all optical elements of the optical system 5 between the illumination device and the workpiece, as well as between the workpiece 2 and the detection means 6, are image-correcting, so that parallel incident light rays are transmitted as parallel light rays towards the detection means, in particular reflected. In general, refractive and / or diffracting optical elements, such as lenses, especially lens arrangements with several lenses arranged in series as optical elements, and / or optical prisms and / or optical plates, could also be used for this purpose. Preferably, no diffracting optical elements are provided.Refractive optical elements are used, particularly to determine the effective length of different partial beam paths. However, the use of plane mirrors is especially advantageous because they are structurally simple, inexpensive components, and can be manufactured with high optical quality to produce a distortion-free shadow image of the tool and project it onto the detection device.

[0080] In the beam path S between the lighting device or light source 4a and the detection device 6, at least one beam path splitter 5s is arranged, more precisely in the beam path between the light source 4a and the workpiece 2. The beam path splitter 5s divides the light emitted by a light source 4a of the lighting device into at least two, here exactly two, separate partial beams S1, S2 ( Fig. 2b) The various partial beams S1, S2 can be directed, preferably simultaneously or with a time delay, onto different workpieces 2, in particular those of different rows R1, R2, in order to produce shadow images of them simultaneously or with a time delay. The rows R1, R2 are arranged in a straight line with a distance between them. The beam splitter 5s is designed as a plane mirror or has several plane mirrors and, more precisely, is composed of such mirrors. The beam splitter 5s is arranged in the beam direction directly in front of the workpiece, so that the light directed by it directly onto the workpiece produces a shadow image. Optionally, several such beam splitters can be provided, which, for example, direct different partial beams onto several workpieces 2.The partial beam paths S1, S2 and the optical elements arranged in them can generally be designed as described for the beam path between the respective light source and the workpiece.

[0081] The beam path divider 5s is arranged here in a fixed position relative to the light source 4a and the other optical elements of the optical system; under certain circumstances, a movable beam path divider can also be used, which in different positions of its movement divides light from the light source 4a and deflects it towards different rows R, whereby the workpieces of these rows are simultaneously or at different times illuminated by the respective light, generating a shadow image, which can generally apply within the scope of the invention.

[0082] The beam splitter 5s, or more generally another optical element, preferably in the form of a plane mirror, is arranged in the light emitted by the light source 4a such that one partial beam S1a of the light beam is blocked and another partial beam S1b is transmitted to another optical element, preferably in the form of a plane mirror, whereby both or optionally more partial beams are directed onto the workpiece 2 to produce a shadow image of it. The beam splitter thus simultaneously provides the plane mirror 5a for the given workpiece 2.

[0083] The optical elements arranged in the beam path S between light source 4a and workpiece 2 are positioned such that the shadow images of the respective workpiece generated by several partial beams S1a, S1b are captured separately by means of the detection means 6 and can preferably be evaluated separately by means of the evaluation unit. The evaluation can be carried out in such a way that the concentricity of the workpiece can be checked. Fig. Reference is made accordingly to point 6.

[0084] The two partial beams S1a and S1b are directed at the workpiece at approximately 90° to each other and strike the workpiece at this angle. The two partial beams S1a and S1b strike the workpiece 2 at least substantially perpendicular to the workpiece's longitudinal axis 2a.

[0085] In the direction of the beam path between the light source 4a and the workpiece 2, a light deflection device 51 of the optical system is provided, wherein, with respect to the direction of illumination of the light in the plane that is at least substantially perpendicular to the longitudinal axis of the workpiece, at least a first part of the light deflection device 511 is arranged in front of the workpiece and a second part of the light deflection device 512 is arranged behind the workpiece. This arrangement of the light deflection device parts 511, 512 in front of and behind the workpiece 2 also relates to the direction of movement of the holding device through the optical system, according to the direction of the arrow. The light deflection devices 511 and 512 are arranged here on opposite sides of a perpendicular of the straight row of workpieces R and are thus positioned in front of and behind the workpiece. This light deflection device 51 is located in the plane that is at least substantially perpendicular to the longitudinal axis of the workpiece.Light or light beams directed perpendicular to the workpiece's longitudinal axis are arranged on the workpiece. Each of the two parts of the light deflection device 511, 512 directs light directly onto the workpiece, generating a shadow image of the workpiece, i.e., different shadow images from different directions. Optionally, more than two such light deflection devices can be provided and / or the light deflection device can comprise more than two parts, thus generating more than two shadow images of the single workpiece. The respective shadow images of the single workpiece 2 are projected separately onto the optical detection device 6 and detected by it independently.The various shadow images of the workpiece, generated by the different parts of the light deflection device 51, can be simultaneously, or optionally with a time delay, detected by the detection means 6, which can also generally apply within the scope of the invention. The beams directed onto the workpiece by the two parts of the light deflection device 511, 512, which generate separate shadow images of the workpiece, form an angle with each other, preferably an angle of ≥ 30° and / or ≤ 145°, preferably ≥ 60° and / or ≤ 120°, preferably approximately 90°. Regarding the design of the light deflection device and the guidance of the beam path, reference is made to the above descriptions of the beam path splitter. The light deflection devices 511 and 512 are designed here as plane mirrors. The light deflection device 511 is also part of the beam path splitter 5s, but this is not mandatory.The light deflection device 512 is not, in this case, part of a beam splitter, but can optionally be used as such. By arranging the light deflection devices 511 and 512, which are positioned in front of and behind the workpiece respectively with respect to the aforementioned direction of illumination and / or the direction of movement of the holding device 3, the front side of the workpiece facing the light source and the back side facing away from the light source can be inspected by generating shadow images. According to the exemplary embodiment, the light deflection devices 511, 512, or optionally all of the provided light deflection devices, which direct the light directly onto the workpiece to generate the shadow image, are also designed as plane mirrors.

[0086] An angle of ≥ 30° and / or ≤ 175°, preferably ≥ 145° and ≤ 35°, more preferably ≥ 60° and ≤ 120°, here approximately 90°, is provided between the rays falling on the workpiece from at least two parts of the light deflection devices 51, here parts 511, 512. The perpendicular to the workpiece array represents at least approximately a bisector of the said angle of the rays directed directly onto the workpiece by parts 511, 512 of the light deflection device.

[0087] Each of the parts 511, 512 of the light deflection devices 51, optionally also in the form of a beam path splitter 5s or generally in the form of an optical element 5a, b, in the exemplary embodiment as a plane mirror, which shines light from the light source 4a directly onto the workpiece to form a shadow image of it, is assigned a corresponding part 5r1, 5r2 of a light deflection device 5r in the direction of the beam path between the workpiece and the optical detection means 6. This applies generally regardless of the arrangement of the parts of the light deflection device 51, i.e., e.g., with regard to the arrangement in front of or behind the workpiece; thus, all parts of the light deflection device 51 can also be arranged in front of or behind the workpiece. As a result, the shadow image produced by the respective light source-side part 511 of the light deflection device 51 is projected onto the light deflection device 5r1 and deflected by it in the direction of the detection means 6.The shadow image generated by the light deflection device part 512 is deflected or projected onto the optical detection device via the corresponding light deflection device part 5r2. Parts 511 and 512, as well as parts 5r1 and 5r2, are designed as separate components. Parts 5r1 and 5r2 are each designed as plane mirrors. This provides the optical detection device with six different shadow images of one and the same workpiece, here from different views or illumination directions of the workpiece.

[0088] The light deflection device 5r1 is part of an optical element 5v, which has two plane mirrors positioned at an angle to each other, i.e., in addition to the plane mirror 5r1, there is another plane mirror 5v1. The light deflection device 5v is constructed here like a beam splitter 5s, so reference is made to the descriptions therein. However, the edge of the light deflection device 5v, where the plane mirrors 5r1 and 5v1 converge or abut each other, faces the detection element 6. The optical element 5v directs the light rays from workpieces of different workpiece series R1 and R2 to the single common detection element 6, which is accomplished here by means of the light deflection device 5n described below.The optical element 5v, with its at least two or exactly two sub-elements 5r1, 5v1, is thus positioned in the beam path between at least one light source, here two light sources, and two workpieces, preferably workpieces from different rows, and a common detection device 6, which detects the shadow images of the at least two workpieces from different rows R1, R2 and preferably transmits them to the evaluation device 7. The optical element 5v therefore combines the shadow images of different workpieces 2 from different rows R1, R2. The detection device detects the shadow images of the workpieces 2, 2' from different rows R1, R2 simultaneously, since the workpieces 2, 2' are arranged at the same height with respect to their passage through the optical system or at the holding device 3. If the workpieces 2, 2' are arranged at the same height with respect to their passage through the optical system or at the holding device 3, the detection device 5v can be used to detect the shadow images of the workpieces 2, 2' from different rows R1, R2 simultaneously.If the workpieces are arranged at different heights on the holding device 3, i.e., when viewed from the side, not one behind the other but offset from each other, the detection means detects the workpieces 2, 2' of different rows R1, R2 at different times, but nothing changes in the beam path with respect to the respective workpiece.

[0089] Furthermore, a light deflection device 5n is provided to deflect the generated shadow images of the respective workpiece towards the optical detection device 6, for example, a camera. The deflection is achieved by reflection. The direction of incidence of the light into the detection device 6 is at an angle, here perpendicular, to the plane E in which the shadow images are generated. The light deflection device 5n is also arranged at 45° to the plane E and / or to the direction of incidence of the light into the optical detection device 6. The light deflection device 5n is designed as a plane mirror. The light deflection device 5n deflects several or all of the partial beams S1a, S1b, which correspond to individual shadow images of the workpiece, onto the detection device 6. The detection device 6 is arranged outside the plane E, which is perpendicular to the longitudinal axis of the workpiece.However, in general, within the scope of the invention, several light deflection devices 5n may optionally be provided to direct the multiple shadow images of a workpiece onto the detection means. This can also apply generally within the scope of the invention.

[0090] The light deflection device 5n deflects partial beams S1, S2 from different workpieces 2, which are arranged here in different rows R1, R2, onto the detection means 6, which can apply independently of or in addition to the deflection of the various partial beams S1a, S1b with respect to a specific workpiece, or in this case applies additionally. This can also apply generally within the scope of the invention.

[0091] The optical elements 511, 512, 5s, which shine light directly onto the workpiece to generate at least one or more shadow images of the workpiece, are arranged such that the light and thus also the shadow image is generated from a central workpiece section, with respect to the workpiece longitudinal direction, or alternatively or additionally, for example, from the free end area of ​​the workpiece, which is opposite the workpiece holder, e.g., a pipette tip opening, a vessel bottom, or the like.

[0092] The inspection system according to Fig. The workpieces 2 are arranged in laterally spaced rows R1, R2. The holding device 3 is designed here, for example, as shown in Fig. 1 shown, or in another suitable manner. Of the several workpiece rows of the holding device, according to Fig. 1 eight such rows are in Fig. Figure 2 shows only two such rows. The holding device 3 is positionally variable relative to the optical system 5, in particular translationally variable, so that when the holding device is moved relative to the optical system 5, the workpieces are guided through the optical system 5 along the longitudinal extent of the rows R. The holding device can be moved continuously so that the workpieces pass through the optical system continuously; if necessary, a stepwise movement of the holding device is also possible. In this way, one of the workpieces of the respective row R enters the examination area of ​​the optical system 5 successively, as is the case for the two in Figure 2. Fig. The two illustrated rows are shown for each workpiece (with corresponding beam path). In the illustrated inspection position of the workpiece, the partial beams S1a, S1b of the light deflection devices 511, 512 intersect. It is understood, however, that—also generally within the scope of the invention—the respective workpiece can also pass through inspection or measurement positions spaced apart from one another in the direction of movement of the holding device, whereby shadow images from different directions and / or from different longitudinal sections of one and the same workpiece are generated in the spaced inspection positions, which can be evaluated individually or together in the evaluation device 7. The respective light source 4a, which is thus assigned to a workpiece or a series of workpieces for generating the shadow image of the respective workpiece, is arranged here between adjacent rows R1, R2, preferably centrally between them.This also applies here to the beam path divider 5s and the light deflection device 5n, and on the opposite side of the given workpiece or workpiece row for the light deflection devices 5r1, 5r1, 5v and the detection device 6. In order to also be able to detect the workpiece rows that laterally delimit the field of workpieces, two further light sources 4a with associated beam path dividers 5s are provided at the lateral boundaries of the field, so that only five light sources 4a with associated beam path dividers 5s are provided for the eight workpiece rows.Furthermore, in the described arrangement of the holding device 3 with more than two or more than three spaced-apart rows of holders for at least or exactly one workpiece each, a light deflection device 5n is provided between the workpiece and the detection device 6, which aligns the shadow images of two workpieces from different workpiece rows R onto a detection device 6. The shadow images of the two workpieces from the different rows can preferably be detected simultaneously by one detection device, or optionally sequentially, particularly if the workpieces from different rows pass through the examination position of the optical system for generating the shadow image(s) of the respective workpiece at different times.This means that for two workpiece rows R, here two adjacent workpiece rows R1, R2, only one optical detection device 6 is required, which is particularly cost-effective and saves installation space, especially with closely spaced workpiece rows. For the eight workpiece rows with one holder according to . Fig. Thus, only four optical detection devices 6, such as cameras, are required. It is understood that the beam path shown in the figure of the exemplary embodiment – ​​as in the other exemplary embodiments – can also be reversed, so that four light sources 4a and five detection devices 6 could be used – which, however, is less advantageous given the higher cost of the detection device compared to the light source.

[0093] The light sources 4a of the lighting device are each designed as a point source, exhibiting a uniform luminous intensity across their entire emission surface. The diameter of the light source is dimensioned such that it illuminates the beam splitter 5s, or a first light deflection device 511 and a second light deflection device 512, respectively, in order to produce the corresponding shadow images. The light sources emit beams of light with parallel rays.

[0094] Fig. Figure 2c shows a modification of the inspection system according to Fig. 2a, b; for further details, reference is made to the explanations provided there. The optical system is designed such that the workpiece 2 to be examined is illuminated simultaneously with two separate partial beams S1a, S1b from a light source 4, in order to generate a different shadow image of the respective workpiece with each partial beam S1a, S1b. The separate partial beams S1a, S1b for the same workpiece are detected by a common detection device 6. The separate partial beams S1a, S1b between the workpiece in its examination position, as in Fig. As shown in Figure 2b, and the detection device 6 have different beam path lengths between workpiece 2 and detection device 6, then in this section the beam path of partial beam S1b is longer than that of partial beam S1a. With a larger difference in the partial beam length, as shown in Figure 2b, the beam path of partial beam S1b is longer than that of partial beam S1a. Fig. 2c, given the depth of field of the scanning objective, the two shadow images could appear with different levels of sharpness. Therefore, in one of the beam paths of the partial beams S1a, S1b between the workpiece and the scanning device, specifically in the longer partial beam S1b, an optical element 5x1 (dashed line) is arranged as an adjustment element. This element aligns the image sharpness of the different shadow images in the scanning device, correcting them to the same level of sharpness. The optical element 5x1 is designed as a prism. The partial beam S1b falls perpendicularly onto the light-entry surface of the prism and exits the prism perpendicularly to its light-emission surface. The prism is a 90° prism, with the light-entry and light-emission surfaces perpendicular to each other. The optical element 5x1 is arranged directly, and therefore generally preferably without a slit, on the light-deflectoring element, here the plane mirror 5n, for example, permanently attached to it.In the partial beam path S1a (in . Fig. (2c not shown) no such adaptation element is provided, although, generally, with suitable design of the adaptation elements, adaptation elements can also be provided in all partial beam paths for a single workpiece. Since two light beams S1, S2 from two different workpieces in different rows, originating from two different light sources, fall onto the light deflecting element 5n, a second optical adaptation element 5x2 is also provided for partial beam path S2b, which is longer than partial beam path S1a. The adaptation elements 5x1 and 5x2 are identical in design for the given beam path geometry, but this is not mandatory. The two adaptation elements 5x1, 5x2 are arranged at the two edge regions of the deflecting device or plane mirror 5n. The shorter partial beams S1a, S2a fall directly onto the deflecting element 5n in the space Z between these.The light emitted towards the detection element 6 by means of the light deflection devices or plane mirrors 5r2 thus falls on the respective adjustment element 5x, the light emitted towards the detection element 6 by means of the light deflection devices or plane mirrors 5r1 falls into the space Z and thus directly onto the deflection mirror 5n.

[0095] Fig. Figure 3 shows an alternative embodiment of the inspection system according to the invention. The differences from the embodiment shown in Figure 3 are described below. Fig. 2 described; moreover, the full details are referred to in the explanations of the exemplary embodiment according to Fig. 2 referenced. Components of the inspection system according to Fig. 3, which components of the exemplary embodiment according Fig. 2, each corresponding to a reference number increased by "10". The inspection system according to Fig. 3 is particularly suitable for examining workpieces in the form of reaction vessels such as sample containers, which have a closed bottom and may have a relatively large width.

[0096] Inspection system 11 according to Fig. In section 3, each workpiece 12 or each row R of workpieces is assigned its own light source 14a of the lighting device 14. The light emitted by the light source 14a is thus projected onto only one workpiece to create a shadow image of it. This allows the shadow image to have a relatively large width, as the light beam from the single light source 14a can illuminate the entire diameter of the workpiece. The light rays incident on the workpiece 12 from the light source 14a also fall at least substantially perpendicular to the workpiece's longitudinal axis 12a. The light rays incident on the workpiece 12 are arranged such that a central section of the workpiece 12 is illuminated to create a shadow image. If necessary, the free end or the bottom area of ​​the workpiece can also be illuminated to create a shadow image, for example, by...The light beam can have a sufficient width so that the shadow image also encompasses the ground area. The "free end" of the workpiece is understood here—as is generally the case within the scope of the invention—to be the workpiece end that is located away from the holding device 13. However, if necessary, the inspection system according to... Fig. 3 the light emitted by a light source 14a is directed onto a beam splitter which produces at least two or more partial beams, each directed onto different workpieces or onto a workpiece from different directions.

[0097] The optical system 15 here includes a light deflection device 15u, which is designed as a plane mirror and directs the light emitted by the light source 14a onto the workpiece 12 to generate a shadow image of it. Furthermore, a light deflection device 15n is provided behind the workpiece 12, i.e., on the side of the workpiece facing away from the light source 14a, which deflects the directly generated shadow image towards an optical detection device 16, such as a camera. The light deflected by the light deflection device 15u is emitted in a direction that lies in the same plane as the light beam directly incident on the workpiece, this plane E being at least substantially perpendicular to the longitudinal axis 12a of the workpiece. By means of another light deflection device 15n, here in the form of a plane mirror, the shadow image is then deflected towards the detection device 6.Projected. By means of a deflection device or plane mirror 15n, shadow images of workpieces in adjacent rows R1, R2 are deflected onto a common detection device and projected. The light deflection device 15n couples the incident light from the plane, which is at least substantially perpendicular or perpendicular to the longitudinal axis of the workpiece, in the direction of the detection device 16.

[0098] The generated shadow images of the workpieces from different, here adjacent, rows R1, R2 are projected, or more precisely reflected, by means of plane mirrors 15v1, 15v2 of the optical element 15v towards the detection element 16 or towards the light deflection device 15n. The detection element 16 captures the shadow images of different workpiece rows, either simultaneously or possibly with a time delay, depending on the temporal arrangement of the two workpieces 12 in their examination or measurement position in the beam path. The optical surfaces or plane mirrors 15v1, 15v2 form an angle with each other, for example, an obtuse angle, here an angle of approximately 90°. The plane mirrors 15v1, 15v2 converge towards an edge or can – as shown – abut an edge.The light deflection device 15v with the two optical surfaces 15v1, 15v2 can be designed as a single component; alternatively, a separate light deflection device can be provided for each of the optical surfaces. Refer to the corresponding descriptions of the light deflection device 5v below. Fig. 2 is referred to.

[0099] The optical axes of the light source 14a, i.e., in which the light is emitted, and / or the optical axis of the detection device 16, i.e., the direction in which light enters the detection device, are each aligned parallel to the workpiece longitudinal axis 12a, possibly independently of one another. However, at least one or both of the optical axes of the light source 14a and the optical detection device 16 may also be aligned in a different direction.

[0100] It goes without saying that even according to the exemplary embodiment of the Fig. 3. A beam splitter can be provided so that the light emitted by a light source can be directed in partial beams onto at least or exactly two preferably adjacent rows of workpieces R in order to produce shadow images of workpieces in these rows. For example, the light-deflector mirror 15u can be arranged in the beam path of the light source 14a so that it deflects only half of the light beam from the source 14a towards one row of workpieces, and next to this, at an angle of, for example, 90°, another light-deflector mirror is arranged, which deflects the other part of the emitted light beam towards another row of workpieces R.

[0101] Fig. 4a, Fig. Figure 4b shows a further embodiment of an inspection system 21 according to the invention. The differences to the embodiments of the Fig. 2 and Fig. As described in Figure 3, reference is made to the full explanations relating to these figures. The number of identical components as in the preceding embodiments is increased by 10.

[0102] The optical system 25 of the inspection system 21 comprises a plurality of mirrors 25b, which are arranged distributed around the circumference of the workpiece 22. The mirrors 25b are advantageously arranged in an arc, more precisely along a segment of a circular arc, around the workpiece 22. Each mirror 25b produces a shadow image of the workpiece, each from a different direction according to the mirror arrangement. Thus, each mirror 25b produces a shadow image of a different circumferential region of the workpiece. The plane of the circular arc segment is arranged at least substantially perpendicular to the longitudinal axis 22a of the workpiece. The optical system 25 is arranged in this way to produce shadow images of a longitudinal segment, here the free end of the workpiece, for example, a pipette tip opening.The arc segment (circular) on which the majority of mirrors 25b are distributed is essentially designed as a semicircle. The mirrors 25b are each designed as plane mirrors.

[0103] The light emitted by the light source 24a is directed by a light deflection device 25a, designed as a plane mirror, towards the plurality of mirrors 25b. The emission surface of the light source 4a and / or the light deflection device 25a, here both, each have a surface to illuminate all of the mirrors 25b with a beam of parallel light rays. Each individual mirror 25b produces a shadow image of the workpiece 22, each from a different direction. A plurality of mirrors 25c, also designed as plane mirrors, are arranged behind the workpiece 22 in the direction of the light beam. Each of the mirrors 25b producing a shadow image has a corresponding mirror 25c for projecting, here reflecting, the respective shadow image towards the detection device. The mirrors 25c are arranged in the straight line connecting mirror 25b - workpiece - mirror 25c.This generates multiple shadow images of the workpiece from different directions. These shadow images are separated from one another and are each captured separately by the detection device 26, i.e., resolved from one another. The detection device 26 captures the different shadow images simultaneously, or possibly with a time delay. The light emitted by the mirrors 25c towards the detection device 26 can be directed laterally past the light deflection device 25a onto the detection device 26, or optionally through the deflection device 25a, which for this purpose can be designed, for example, as a semi-transparent mirror exhibiting both reflective and transmissive properties.

[0104] The optical axis of the light source 24a is arranged here at an angle, more precisely perpendicularly, to the workpiece longitudinal axis 22a, resulting in a structurally compact embodiment particularly well-suited to specific construction situations. If necessary, however, the optical axis of the light source 24a can also be aligned in a different direction relative to the workpiece longitudinal axis 22a by means of suitable light deflection devices. The optical axis of the detection element 26 is arranged here parallel to the workpiece longitudinal axis 22a; however, a different orientation of this optical axis can also be achieved by means of light deflection devices arranged in the beam path.

[0105] According to Fig. 4a, Fig. 4b Each workpiece row is assigned a separate light source 24a and a separate detection device 26. This allows the workpiece area to be irradiated with high light intensity and enables particularly high precision in the inspection of the workpiece. If necessary, however, even in this embodiment, the light emitted by the light source 24a can be directed to a beam splitter, as shown in Fig. 2 is shown in principle, so that here too, different workpieces or workpieces from different series can be checked using a light source.

[0106] Fig. Figure 5 shows the structure of the inspection system 21 according to the design as described above. Fig. 4a, Fig. 4b with several optical detection means 26, each of which is assigned to an optical system 25 for examining a workpiece (the light sources 24a are not shown). The optical systems 25 for examining the workpieces of different workpiece series are arranged offset from one another in the direction of movement of the holding device 23 (direction of arrow), which enables a structurally compact embodiment and adaptation of the system even to closely adjacent workpiece series. This design can also be implemented in all other embodiments or generally within the scope of the invention. The holding device 23 can, for example, be configured accordingly. Fig. 1. The majority or all of the arc-shaped mirrors 25b at the respective workpiece inspection position are each arranged in a block or common housing 25bg. The same applies to the arrangement of the mirrors 25c in a common housing 25cg, which are assigned to the same workpiece as the mirrors 25b. This significantly simplifies the mounting of the mirrors, and the mirrors 25b and 25c can be adjusted relative to each other within the housing. The housings 25bg and 25cg are spaced laterally apart to leave a track along which the respective series of workpieces can be passed through the optical system by means of the holding device 23.

[0107] Fig. Figure 6 shows a representation of the optical detection means 26 of the inspection system 21 according to Fig. 4a and Fig. 4b captured shadow images. The individual shadow images B, here five, corresponding to the number of mirrors in the arrangements of mirrors 21b and 25c on the light source and detection medium sides respectively, are spatially separated from one another, so that the respective shadow images are separate and can be evaluated separately. Separate evaluation means that the individual evaluations of the shadow images can be compared, for example, to check the workpiece's rotation. It is understood that the bright image areas of the different shadow images of the same workpiece can overlap, as long as the different workpiece shadows, especially those of the free end of the workpiece, are sufficiently resolved separately.The representation of a single shadow image B corresponds in principle to a shadow image as generated by the other embodiments of the inspection system or generally within the scope of the invention, taking into account the different workpiece section being inspected and, if applicable, other special features of the respective inspection system.

[0108] Fig. Figure 7 shows a further embodiment of an inspection system 31 according to the invention, wherein the differences to the inspection systems described above are described below, and reference is made in full to these embodiments. Identical components are provided here with reference numerals increased by 10.

[0109] The light emitted by the light source 34a is directed onto a light deflection device 35a. Optionally, further light deflection devices, and optionally a beam splitter, may be arranged between the light source 34a and the light deflection device 35a. The light deflection device 35a is designed as a plane mirror. Specifically, the light deflection device 35a is a semi-transparent mirror, thus exhibiting both reflective and transmissive properties. The optical system of the inspection device includes at least one semi-transparent mirror, in this case, the mirror 35a.The light emitted by the light source 34a is thus directed via the semi-transparent light deflection device 35a towards the workpiece 32 to be examined, specifically, by way of the further light deflection device 35b, into the plane that is at least substantially perpendicular to the longitudinal axis of the workpiece, and subsequently, by way of example, by means of a beam splitter 35s onto various workpieces 22 of different workpiece series R1, R2. The beam splitter 35s with two optical surfaces 35s1, 35s2 designed as plane mirrors can be arranged like the optical element 15v according to . Fig. 3. It is understood that, generally, the angle between the two surfaces of the beam splitter or optical element 15v depends on the specific arrangement of the beam path, so that this angle—generally within the scope of the invention—can be adapted to the respective situation. The optical axis of the light source 34a is arranged in the longitudinal direction of the workpiece rows R; however, with a suitable arrangement of light deflection devices, it can also be oriented differently if necessary. It is understood that a modified embodiment of the inspection system can also be implemented, for example, without a beam splitter, whereby each workpiece row can be assigned a separate light source 34a.In general, within the scope of the invention, the plane mirrors of the optical system are not designed as partially transparent plane mirrors and preferably reflect the incident light beam as completely as possible or completely in the direction of emission of the respective mirror, which can apply to all mirrors of the optical system, except for the partially transparent plane mirror provided in a preferred embodiment.

[0110] Fig. Figure 7a shows the beam path between light source 34a and detection device 36 only incompletely; this is shown in Fig. Figure 7b is shown schematically. The light emitted by the optical surfaces 35s1, 35s2 onto the respective workpiece 32, which produces the respective shadow image of the workpiece in row R1 or R2, is reflected by the plane mirrors 35c1, 35c2 onto the light deflecting device 35b, and from there towards the semi-transparent light deflecting device 35a, and then onto the detection device 36, which detects separate shadow images of the workpieces 32 from different rows. The beam path of the detection device 36 is arranged parallel to the longitudinal axis 32a of the workpiece, although this is not strictly necessary if further light deflecting devices are interposed.

[0111] This arrangement of a semi-transparent light deflecting device 25a can also be implemented in connection with all other embodiments or generally within the scope of the invention.

[0112] Fig. 8 shows in the Fig. 8a, Fig. Figure 8b shows two different embodiments of optical elements 45 of an inspection system 41 according to the invention. These two embodiments can also be implemented generally within the scope of the invention or with reference to the exemplary embodiments, so that the beam path can be adapted to the respective requirements.

[0113] Fig. Figure 8a shows a section of the beam path with a light deflection device 85v of an optical system 85, corresponding to the light deflection device 15v according to Fig. 2, which projects or deflects two different partial beams S1, S2 from workpieces of different rows R1, R2 from two light sources 84a onto a detection device 86 (camera), here a common detection device. The arrows in Fig. Figure 8 shows the direction of movement of the workpieces 82 as the holding device moves through the optical system. The light deflection device 85v has two optical surfaces 85v1, 85v2, here in the form of plane mirrors, which are positioned at an acute angle to each other, here at an angle of approximately 35 to 55°. With respect to the direction of movement of the workpieces (arrow), the light sources 84a are arranged behind the device 85v along the connecting line "detection means 86 - light deflection device 85v". The rays of the beam path form an obtuse angle. For further details, please refer to the description of the beam path in [reference to relevant section]. Fig. 2 referred.

[0114] According to Fig. In Figure 8b, the light deflection device 95v is modified compared to the light deflection device 85v. Here, too, light from the two light sources 94a is directed with partial beams S1, S2 onto the respective workpiece 92, generating a shadow image of it, and the shadow image is directed via the light deflection device 95v onto the detection element 96. The light deflection device 95v here has two optical surfaces 95v1, 95v2, which are set at an obtuse angle, here approximately 115°. With respect to the direction of movement of the workpieces (arrow), the light sources 84a are arranged in front of the device 85v with respect to the connecting line "detection element 96 - light deflection device 95v". The rays of the beam path form an acute angle. If necessary, in the exemplary embodiments of the Fig. 8a, Fig. 8b or, more generally, within the scope of the invention, the angle between the two optical surfaces may also be approximately 90°.

[0115] Starting from Fig. 8. It is understood that the corresponding geometry of the beam path can also be provided in the beam path between the respective light source and the workpiece. The beam paths according to Fig. 8a, Fig. 8b can also be used for other light deflection directions, e.g. for beam splitters, e.g. the beam splitter 5s according to Fig. 2. Furthermore, additional light deflection devices may be provided according to the arrangement of the light source and the detection device in relation to the workpiece rows.

Claims

[1] Inspection system (1) for checking elongated workpieces (2), in particular injection-molded parts such as pipette tips, which have a workpiece longitudinal axis (2a), comprising: - a holding device (3) for holding at least one or a plurality of workpieces (2) to be checked, which are arranged on the holder (3a) preferably in several rows separated from one another by a distance d, - a lighting device (4) comprising at least one light source (4a), - at least one optical detection means (6), wherein the workpiece (2) is arranged in the beam path of the light emitted by the light source (4a) between the light source (4a) and the optical detection means (6), and wherein the optical detection means (6) detects the image of the workpiece generated by the illumination device (4), - an optical system (5) for directing the light emitted by the light source (4a), preferably laterally, onto the workpiece (2) to be inspected, which is arranged on the holder (3a), and from the workpiece (2) onto the optical detection means (6), - preferably an evaluation device (7) which is connected to the optical detection means (6) in a signal-transmitting manner and enables an evaluation of the workpiece image, characterized by , (i) that the holding device (3) has at least two spaced-apart rows of holders for at least one or exactly one workpiece (2) each, and that a light deflection device (5n) is provided between the workpiece (2) and the detection means (6), which aligns the shadow images (73) of two workpieces of different rows onto the detection means (6), and / or (ii) that the holding device (3) has at least two spaced-apart rows of holders for at least one or exactly one workpiece (2) each, and that a beam path splitter (5s) is provided between the light source (4a) and the workpiece (2), which beam path splitter divides the beam path (S) of the light source (4a) and preferably simultaneously aligns it to different rows. [2] Inspection system (1) according to claim 1, characterized by that the optical system (5) is designed to generate a shadow image of the workpiece (2) from at least one direction transverse to the workpiece longitudinal axis (2a) and to project the generated shadow image onto the detection means (6). [3] Inspection system (1) according to claim 1 or 2, characterized by , that (i) the optical system (5) comprises at least one plane mirror (5a; 5b) which directs the light from the light source (4a) onto the workpiece (2), and / or (ii) the optical system (5) in the beam path between the light source (4a) and the workpiece (2) consists exclusively of plane mirrors and / or that the optical system (5) in the beam path between the workpiece (2) and the optical detection means (6) consists exclusively of plane mirrors. [4] Inspection system (1) according to claim 3, characterized by that the plane mirror is arranged in the beam path between the light source (4a) and the workpiece (2) directly in front of the workpiece (2). [5] Inspection system (1) according to one of claims 1 to 4, characterized by that the optical system (5) has at least two plane mirrors arranged one behind the other in the beam path between the light source (4a) and the workpiece (2). [6] Inspection system (1) according to one of claims 1 to 5, characterized bythat the optical system (5) is designed such that the rays incident on the workpiece (2) which produce the shadow image (73) of the workpiece are a light bundle of rays aligned at least substantially parallel to one another. [7] Inspection system (1) according to one of claims 1 to 6, characterized by that the beam path (S) has at least one beam path splitter (5s) which splits the light emitted by a light source (4a) into at least two separate partial beams (S1; S2) and directs the at least two partial beams onto one and the same workpiece (2) to produce at least two shadow images (73) of the same. [8] Inspection system (1) according to claim 7, characterized by that at least two or all of the partial beam paths are designed according to one of claims 2 to 6. [9] Inspection system (1) according to one of claims 1 to 8, characterized bythat a light deflection device (51) of the optical system is provided in the beam path between the light source (4a) and the workpiece (2) in the light radiated onto the workpiece (2) at least substantially perpendicular to the workpiece longitudinal axis (2a), and (i) that with respect to the direction of irradiation of the light in the plane at least substantially perpendicular to the workpiece longitudinal axis (2a) and / or (ii) that in the direction of movement of the holding device (3) through the optical system (5), at least a first part of the light deflection device (511) is arranged in front of the workpiece (2) and a second part of the light deflection device (512) is arranged behind the workpiece (2), and that the two parts of the light deflection device (511; 512) each produce a shadow image (73) of one workpiece (2). [10] Inspection system (1) according to claim 9, characterized bythat the part of the light deflection device arranged in the plane in front of and / or behind the workpiece (2) with respect to the direction of incidence comprises at least one plane mirror and / or that the parts of the light deflection device are each designed as plane mirrors. [11] Inspection system (1) according to claim 10, characterized by that the part of the light deflection device arranged in front of and / or behind the workpiece (2) is arranged directly in front of or behind the workpiece (2) in order to produce a shadow image (73) of the workpiece (2). [12] Inspection system (1) according to one of claims 9 to 11, characterized by that the light deflection devices (511; 512) arranged in the plane in front of and behind the workpiece (2) with respect to the direction of incidence, which each produce a shadow image (73) of the workpiece (2), are arranged at an angle of ≥ 20° and / or ≤ 170°, preferably approximately 90°, to one another with respect to the workpiece (2). [13] Inspection system (1) according to one of claims 1 to 12, characterized by that the optical system (5) comprises a plurality of mirrors (5a; 5b) in the beam path upstream of the workpiece (2), each preferably as a plane mirror, which are arranged distributed around the circumference of the workpiece (2) and which each produce a shadow image (73) of the workpiece (2). [14] Inspection system (1) according to one of claims 1 to 13, characterized bythat the optical system (5) comprises a plurality of mirrors (5r1; 5r2) in the beam path downstream of the workpiece (2), which mirrors are arranged distributed around the circumference of the workpiece (2), and that at least one or all of the mirrors (5r1; 5r2) downstream of the workpiece (2) are assigned to one of the plurality of mirrors (5a; 5b) generating a shadow image (73), and that the mirrors (5r1; 5r2) downstream of the workpiece (2) deflect the shadow image generated by the respective mirror in the direction of the detection means (6). [15] Inspection system (1) according to one of claims 1 to 14, characterized by that mirrors (5a; 5b) producing a shadow image (73) and mirrors (5r1; 5r2) arranged downstream of the workpiece (2) in the beam path each partially surround the workpiece (2). [16] Inspection system (1) according to one of claims 1 to 15, characterized bythat a plane mirror (5u) is provided on the illumination side of the workpiece (2), which directs light emitted by the illumination device (4) directly onto several or all of the mirrors (5a; 5b) arranged distributed around the circumference of a workpiece (2), and / or that a plane mirror (5n) is provided on the detection means side of the workpiece (2), which projects shadow images (73) of the workpiece (2) from several or all of the mirrors (5r1; 5r2) arranged distributed around the circumference of a workpiece (2) towards the detection means (6). [17] Inspection system (1) according to one of claims 1 to 16, characterized by that the detection means (6) is designed to detect the shadow images (73) of workpieces (2) of different rows simultaneously. [18] Inspection system (1) according to one of claims 1 to 17, characterized bythat the detection means (6) and / or a light deflection device (51) which directs light from the light source (4a) to different rows, and / or that a light deflection device which deflects light from the workpiece (2) to the detection means (6) is arranged between the rows. [19] Inspection system (1) according to one of claims 1 to 18, characterized by that the light source of the lighting device is at least essentially a point source. [20] Inspection system (1) according to one of claims 1 to 19, characterized by that the optical axis of the light source (4a) of the illumination device (4) and / or of the detection means (6) is aligned parallel to the workpiece longitudinal axis (2a). [21] Inspection system (1) according to one of claims 1 to 20, characterized bythat the optical system (5) has an optical element which is designed to be partially transparent and which is arranged both in the beam path of the light or beam path emitted by the illumination device towards the workpiece (2), and at the same time is arranged in the light falling from the workpiece (2) in the direction of the detection means (6). [22] Inspection system (1) according to one of claims 1 to 21, characterized bythat the optical system (5) is designed to irradiate the workpiece (2) to be examined with at least two separate partial beams (S1; S2) of at least one light source (4a) in order to generate a different shadow image (73) of the respective workpiece (2) with each partial beam, that the separate partial beams have a different beam path length between the workpiece (2) in its examination position and the detection means (6), and that an optical element is arranged in at least one of the beam paths of the partial beams between the workpiece (2) and the detection means (6) in order to match the image sharpness of the different shadow images in the detection means (6). [23] Inspection system (1) according to one of claims 1 to 22, characterized bythat the optical system (5) is designed to generate an undistorted shadow image (73) of the workpiece (2) from at least one direction transverse to the workpiece longitudinal axis (2a) and / or to project the generated shadow image undistorted onto the detection means (6). [24] Inspection method for checking elongated workpieces (2) using the inspection system (1) according to one of claims 1 to 23. [25] Inspection method according to claim 24, characterized bythat the holding device (3) for holding at least one or a plurality of workpieces (2) to be inspected is moved relative to the optical system (5) in order to transfer the workpiece (2) to be inspected from a non-inspection position into an inspection position on the optical system (5) which generates the shadow image (73) of the workpiece (2), and that the exposure time of the workpiece (2) for generating its at least one shadow image is less than or equal to 1 millisecond.

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