EP4278171A1

EP4278171A1 - Inspection system

Info

Publication number: EP4278171A1
Application number: EP22701170.7A
Authority: EP
Inventors: Bodo Ergert
Original assignee: Ma Micro Automation GmbH
Current assignee: Ma Micro Automation GmbH
Priority date: 2021-01-13
Filing date: 2022-01-11
Publication date: 2023-11-22
Also published as: US20240142388A1; WO2022152682A1; DE102021100562A1

Abstract

The invention relates to an inspection system for checking elongate workpieces (2), more particularly injection-moulded parts such as pipette tips, which have a workpiece longitudinal axis, comprising: (i) a holding device (3) for holding a plurality of workpieces to be checked, which are arranged on the holder preferably in a plurality of rows (R1, R2) separated from one another by a distance d, (ii) an illumination device (4) comprising at least one light source (4a), (iii) an optical detection means (6), the workpiece being arranged in the beam path (S1, S2) of the light emitted from the light source between the light source and the optical detection means, and the optical detection means detecting the image of the workpiece generated by the illumination device, (iv) an optical system (5) for orienting the light emitted from the light source preferably laterally towards the workpiece to be checked arranged on the holder, and from the workpiece towards the optical detection means, (v) preferably an evaluation device (7), which is connected in a signal-transmitting manner to the optical detection means and permits an evaluation of the workpiece image. The optical system is designed to generate a preferably non-distorted shadow image of the workpiece from at least one direction transverse to the workpiece longitudinal axis and to project the shadow image preferably in non-distorted fashion onto the detection means.

Description

Inspection sy s tem

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

Generic inspection systems are used in particular to carry out a quality check on elongated injection molded parts immediately after they have been manufactured. Workpieces of this type are used, for example, in the medical field, such as pipette tips, cup-shaped receptacles for medical samples to be examined or substances to be analyzed or the like. Workpieces of this type must be produced with very high precision, since this would otherwise impair the working methods carried out using such workpieces, such as, for example, analysis methods. For example, defects can occur in workpieces produced by injection molding, such as unwanted burrs, depressions, irregularities in the geometry of the workpiece such as distortion or the like, but in particular areas that have not been sufficiently injected, which leads to workpieces of this type being rejected. High demands are therefore placed on the inspection system with regard to the detection of faulty workpieces.

Furthermore, inspection systems of the generic type are often an integrated part of an automated production line, which usually starts with the production of the workpieces in a shaping tool such as a an injection molding machine, from workpiece testing to packaging of the workpieces. However, high production speeds also require correspondingly short inspection times for the respective workpiece using the inspection system. There is thus a requirement that the inspection system in a such a manufacturing system can be integrated. Furthermore, for this purpose the inspection system must have a compact design, since the workpieces are often close together on the holder and/or little installation space is available.

An inspection device is known from DE 10 2017 120 376 A1, in which the respective workpieces can be checked as they pass through the inspection device. This inspection device has a concave mirror arrangement in order to use a camera to record an image of the outside of the workpiece reflected in this mirror. However, the disadvantage of this device is that the generated mirror image of the workpiece has greater optical distortions compared to the actual workpiece, which leads to unreliability of the testing method. Dimensional tests and measurements are only possible to a very limited extent or not at all with the concave mirror arrangement. Furthermore, it has been found that the use of a mirror image of the workpiece to be examined is disadvantageous for certain applications and that certain workpiece defects, such as small burrs, inaccuracies in the opening of the pipette tip or, in particular, surface defects such as poor spraying of workpiece areas are not always adequately detected.

The invention is therefore based on the object of providing a generic inspection system which partially or completely eliminates the disadvantages described, enables a particularly reliable detection of defects in the workpiece and which is inexpensive. Furthermore, the task is to provide a corresponding inspection method for checking workpieces.

This object is solved by an inspection system according to claims 1 , 17 and 19 , and by an inspection method according to claim 26 . Preferred developments of the subject matter of the invention result from the dependent claims.

The inspection system according to the invention according to claim 1 has a 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 projects it undistorted onto the detection means , or . which is trained for this.

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 in particular insufficient spraying of superficial component areas, especially in the area of an end section of the respective workpiece such as a tip or a bottom area, can be detected particularly reliably. The shadow image here has a very high contrast, namely a darker or darker or black silhouette to the surrounding, lighter area of the workpiece environment, which enables a particularly reliable inspection. Inadequate superficial spraying can be recognized as a missing area of the edge area of the silhouette. Ridges, local elevations, film deposits of excess material or other irregularities are also particularly easy to recognize. Such workpiece defects, in particular also in the case of injection-molded parts, can be detected particularly reliably and with high image sharpness by means of the workpiece silhouette due to the high light/dark contrast of the same to the adjacent image area. This also applies in particular to the free end of the respective workpiece that faces away from the workpiece holder, such as for example in the area of a pipette tip opening. Furthermore, tolerance deviations of the workpiece geometry can be detected particularly reliably by the shadow image.

This applies in each case in particular to the area of said free end of the workpiece, such as in the area of a pipette tip opening or the bottom area of a vessel.

It has been found that due to the high contrast of the Shadow image to the surrounding image area particularly short examination times for the workpiece or Exposure times are possible, which can also be in the range of a few microseconds. The inspection system can thus be used particularly advantageously in an automated production line for manufacturing the workpiece, with the process speed of the production line only being able to be reduced very slightly or not at all as the workpiece passes through the inspection system, i.e. the production line can also be operated continuously at high speed , without affecting the sharpness of the generated shadow image or its evaluation.

Furthermore, due to the mentioned high contrast of the silhouette, a relatively simple evaluation algorithm with a high evaluation speed can be used in the evaluation unit, which is also beneficial for a high production speed of the production line. In addition, it has been found that due to the relatively simple evaluation algorithm and/or the sharpness of the shadow image, the evaluation unit can be used to determine particularly reliably whether the respective workpiece is correct or not correct and must be removed.

The advantages described arise in particular in comparison with inspection systems in which the image of the workpiece is generated in incident light onto it, for example by generating a mirror image of the same, with a high proportion of light then resulting from diffusely emitted light from the workpiece.

In each case, the workpiece can in particular be an injection-molded component. The workpiece can, for example, also be a container such as for analytical purposes and/or for carrying out chemical reactions on a micro scale, without being limited to this, so that relatively small workpieces can also be checked very reliably.

Preferably, the optical system is designed as possible to generate a low-distortion, preferably at least essentially undistorted or undistorted shadow image of the workpiece from at least one direction transverse to the longitudinal axis of the workpiece and/or to project the generated shadow image onto the detection means with as little distortion as possible or preferably at least essentially undistorted or undistorted. Imaging errors of the workpiece, as are the case when curved concave mirrors are used, are reduced or avoided in this way. This increases the reliability of workpiece inspection. The optical system of the inspection system according to the invention therefore preferably has no curved concave mirrors, particularly preferably no optical elements with curved optical surfaces such as, for example, curved reflection surfaces, except for the optics of the light source and/or lens of the detection means. In principle, however, a certain, generally rough, inspection of the workpieces can also be carried out with the generation of distorted shadow images.

The lighting device can include a number of light sources, in particular when a number of workpieces or a number of rows of workpieces are to be inspected simultaneously, under certain circumstances, by means of the inspection system. The workpiece to be examined is in each case preferably irradiated by precisely one light source to produce a shadow image thereof, with one light source optionally also being able to irradiate several workpieces, preferably simultaneously, in particular using a beam path splitter. If necessary, several light sources can irradiate a workpiece, for example from different directions, possibly also for the simultaneous or temporally offset generation of several shadow images of the given workpiece from different directions. The workpieces can be guided past the respective light source or several light sources by means of a movable holding device in order to check the respective workpiece using the shadow image.

The optical detection means can preferably be designed as a camera, but also in other suitable ways, such as, for example as an optical sensor, in particular a surface sensor, or the like. A camera as a detection means has proven particularly useful, since it reliably detects the shadow image of the workpiece and enables image processing of the shadow image in a simple manner. Processing of the camera image by a corresponding evaluation device is particularly easy. The detection means is preferably stationary during the detection of the two or more shadow images of workpieces from different rows of workpieces. arranged in an unchanged position relative to the optical system of the inspection device and/or arranged relative to the light sources generating the respective shadow images.

The inspection system preferably includes an evaluation device which is connected to the optical detection means in a signal-transmitting manner and any material defects can be determined and analyzed by means of the evaluation device. In particular, the evaluation device can compare the silhouette of the workpiece (generally: "silhouette") recorded by means of the detection means with a reference image of a defect-free workpiece. A corresponding reference component can also be stored in the evaluation device as a defect-free workpiece in order to carry out the comparison or the evaluation. It goes without saying that the shadow image can also be compared with a data record which corresponds to a defect-free workpiece 12. The evaluation can generally be carried out by an image processing method, a computational method or in another suitable manner.

Preferably, the optical detection means and the evaluation device connected to it in a signal-transmitting manner, which evaluates the detected shadow images preferably with a computing device, are configured in such a way that the concentricity of the workpiece can be detected or is calculable and / or determined or. is calculated . The concentricity of the workpiece is understood to mean that directions at an angle to one another, which are each arranged perpendicular to the longitudinal axis of the workpiece, one or more longitudinal sections, preferably comprising the free end of the workpiece, each in the Workpiece longitudinal axis is arranged / are. The two directions mentioned can in particular enclose an angle of 90° to one another. When the workpiece rotates about its longitudinal axis, the position of the free workpiece relative to its longitudinal axis does not change when the workpiece is viewed in its longitudinal direction, viewed from the free end of the workpiece. The image of a round workpiece end, such as a round pipette tip opening, thus appears as a circle with the same diameter of the free end as the workpiece rotates. The inspection system according to the invention is particularly adapted to such a round trip or To be able to reliably detect deviations from this.

In order to generate an at least substantially undistorted or undistorted shadow image of the workpiece, the optical system preferably has one or more plane mirrors, which have proven to be particularly advantageous in order to enable the desired reliable workpiece inspection and to generate a shadow image with as little or no distortion as possible and/or in order to project this undistorted onto the detection means. In general, within the scope of the invention, "undistorted" is also understood to mean in particular at least essentially 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, with preferably several or all of the optical elements of the optical The system between the light source and the workpiece consists of plane mirrors. By using the plane mirror or mirrors, it is possible overall to produce a particularly low-distortion or distortion-free image of the workpiece, in particular also in the form of a shadow image of the workpiece, since optical imaging errors are reduced or avoided. In addition, plane mirrors are particularly inexpensive optical elements that can be produced, for example in contrast to a complicated lens system, and require only little installation space, which is of particular advantage in the case of workpieces to be examined that are close together. The optical system preferably has at least two or more plane mirrors arranged one behind the other in the beam path in the beam path between the light source and the workpiece. For this purpose, all of the optical elements between the light source and the workpiece are preferably designed as plane mirrors, ie only plane mirrors are provided. Preferably, in particular in combination with this, at least one or more or all of the optical elements between the workpiece and the optical detection means are designed as plane mirrors, ie only plane mirrors are provided. The optical element of the optical system, which is arranged directly in front of the workpiece and/or directly behind the workpiece in the direction of the beam path, is preferably a plane mirror. As a result, a particularly low-distortion or practically distortion-free generation of a shadow image workpiece and / or a particularly low-distortion or. practically distortion-free detection of the generated shadow by the optical detection means, which allows a particularly reliable inspection of the workpiece is possible.

The optical system is preferably designed in such a way that the rays incident on the workpiece, which generate the shadow image of the workpiece, are a light bundle of rays that are at least essentially parallel or aligned parallel to one another. Preferably, in particular in combination with the above feature, the rays of the silhouette incident on the optical detection means are aligned at least essentially parallel or parallel to one another. This enables a shadow image of the workpiece to be generated with particularly little or no distortion. The rays of the light beam incident on the workpiece can be reversed with respect to the direction of incidence of the light beam on the workpiece ± 20°, preferably ± 10° or ± 5° or ± 2 ° diverge resp . converge, particularly preferably these are parallel to each other. The cross section of the light beam here preferably covers the workpiece section to be examined in its entire width or length. its entire cross-section. Particularly advantageously, the beam path between the illumination-side optical element immediately in front of the workpiece and/or the detection means-side optical element immediately downstream of the workpiece is aligned at least essentially perpendicularly or perpendicularly to the longitudinal axis of the workpiece. As a result, material defects and deviations from the desired geometry in the area of the free end of the workpiece can be detected particularly reliably. The beam path between the optical element on the illuminating means side and the workpiece and/or the beam path between the optical element on the detecting means side and the workpiece, with the optical element being arranged directly on the workpiece in relation to the respective beam path, can have an angle of 20° or 15°, preferably 10° or 5°, particularly preferably approx. Include 0° to the perpendicular of the longitudinal axis of the workpiece. The optical element arranged directly on the illuminating means side and/or on the detecting means side, which is therefore arranged closest to the workpiece in the beam path, is preferably a plane mirror.

The beam path of the light emitted by the illumination device and detected by the optical detection means is preferably telecentric on the object side and/or on the image side, particularly preferably on both sides. In particular, the optical detection means can have a telecentric lens. This enables at least essentially undistorted generation of a shadow image of the workpiece and its at least essentially undistorted or undistorted detection by the detecting means, and thus particularly reliable checking of the workpiece to be examined's freedom from defects. The light beams impinging on the workpiece are generally preferably parallel beams. In general, the light beams impinging on the optical detection means are particularly preferably parallel beams.

The beam path preferably has at least one beam path splitter, which separates the beam from the light source of the lighting unit Direction emitted light splits into at least two separate partial beams and the at least two partial beams on the workpiece, d. H . one and the same workpiece, aimed at generating at least two shadow images of the same. In this way, a shadow image of the workpiece can be generated from several different directions, whereby a particularly reliable detection of any workpiece defects is possible, which can be detected to different degrees by the optical detection means when viewing the workpiece from different directions. The beam path splitter preferably has optically active surfaces which are designed as plane mirrors and cause the beam to be split. All of the optically effective surfaces of the beam path splitter are preferably designed as plane mirrors. For example, the beam path splitter can be in the form of two plane mirrors arranged at an angle to one another, with the apex of the angle preferably being positioned in the beam path. At the vertex of the angle, the two optical elements, in particular plane mirrors, of the beam path splitter can converge in an edge. The angle enclosed between the two optical elements of the beam path splitter can be <180° or <170°, in particular 145° to 30°, particularly preferably 120° to 60°, in particular approx. 90 °, amount, but also, for example. 160° to 90°, the included angle being arranged on the side of the vertex facing away from the beam path. In addition, this results in a particularly cost-effective design of the inspection system, since, for example, independent lighting devices for generating a respective shadow image of the workpiece from a specific direction are avoided in each case. Alternatively, a beam path splitter, for example. can also be built up in that the light emitted by the lighting device is emitted onto a first optical element, preferably a plane mirror, here occupies an illuminated area Fl, which is preferably radiated with at least essentially uniform luminance over the area, and in this area the light is emitted onto at least two or more optical elements with a respective surface F2, which are preferably each designed as plane mirrors. The extent of the light source, for example also as Point source can be at least the area Fl. The surface F1 is preferably larger than the surface F2, preferably the surface F1 is at least as large as the sum of the surfaces F2, the light radiated from the surfaces F2 preferably being radiated directly onto the workpiece to produce shadow images of the same. The number of shadow images generated can correspond to the number of areas F2 provided. The surfaces F1 and F2 are each preferably flat surfaces, preferably each formed by a plane mirror.

The beam path preferably has at least one beam path splitter, which divides the light emitted by the light source of the illumination device into at least two separate partial beams and aligns the at least two partial beams with different workpieces to generate at least two shadow images of the different workpieces. This reduces the outlay on equipment and the system is particularly suitable for examining workpieces that are close together, ie, workpieces that are generally arranged close to one another on the holder. With regard to its configuration, reference is made to the explanations relating to the beam path splitter described above.

The partial beam paths of the inspection system are preferably designed according to claim 8, as described in general for the beam path within the scope of the invention. The optical elements of the at least two or all of the partial beam paths thus preferably have 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 designed accordingly for all of the partial beam paths that are generated by an illumination device. As a result, a particularly low-distortion or at least essentially distortion-free generation and detection of the shadow image(s) of the respective workpiece is possible.

From the irradiation of the workpiece with different partial Radiating from different directions, the shadow images generated in this way can also be used in particular to determine a rotation of the examined workpiece area, in particular the free end thereof, and in particular to calculate it using the appropriately configured evaluation device. The partial beams, which are aligned with the workpiece and form an angle with one another, are preferably arranged in a plane perpendicular to the longitudinal axis of the workpiece.

A light deflection device of the optical system is preferably provided in the beam path between the light source and the workpiece in which the light radiated onto the workpiece at least essentially perpendicularly or perpendicularly to the longitudinal axis of the workpiece, ie preferably in a plane perpendicular to the longitudinal axis of the workpiece. Here, (i) in relation to the irradiation direction of the light in the plane that is at least essentially perpendicular to the longitudinal axis of the workpiece in the direction of the workpiece and/or (ii) in the direction of movement of the holding device through the optical system, it is provided that 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 said irradiation direction or Movement device of the holding device, with the two parts of the light deflection device each producing a shadow image of the workpiece. Said irradiation direction of the workpiece is preferably the direction in which the light, which is coupled directly into the plane perpendicular to the longitudinal axis of the workpiece, or is deflected, radiates towards the workpiece. A light deflection device of the optical system is therefore preferably provided in the direction of the beam path from the illumination device to the detection means in the beam path upstream of the workpiece, which is arranged in a plane perpendicular to the longitudinal axis of the workpiece, in which in the direction of radiation the light is directed onto the workpiece or in the movement device of the holding 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. The described first and second parts of the light deflection device can each be arranged directly in front of the workpiece in relation to the beam path. The parts of the light deflection device arranged in front of and behind the workpiece in relation to the irradiation direction onto the workpiece are thus directed in different directions to produce shadow images onto the workpiece, these light beams forming an angle to one another. This angle can be, for example, 145° to 35°, preferably 60° to 120°, particularly preferably approx. 90 °, without being limited to this. This creates shadow images in different views of the workpiece and enables the workpiece to be checked over a larger circumference, with the light deflection devices arranged in front of and behind the workpiece preferably being radiated in the direction perpendicular to the longitudinal axis of the workpiece in the direction of the workpiece. In particular, the concentricity of the workpiece can also be determined from the shadow images of the different views, for example calculated by means of the evaluation device. In this embodiment of the optical system of the inspection system, at least one part or several or all parts of the light deflection device, which is arranged in front of and/or behind the workpiece in relation to the direction of the beam path, is particularly preferably designed as a plane mirror, which means a particularly low-distortion or at least enables essentially distortion-free imaging of the workpiece. The part of the light deflection device designed as a plane mirror is preferably directly in front of or behind the beam path. arranged behind the workpiece. Preference is given to two or more parts of the light deflection device, preferably in the form of plane mirrors, which 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, which are arranged behind the workpiece in the direction of the beam path. arranged in one plane. This plane is preferably arranged at least essentially perpendicularly to the longitudinal axis of the workpiece; this plane can, for example, be at an angle of 25 ° or 15°, particularly preferred 5° to the longitudinal axis of the workpiece; this plane is preferably arranged perpendicular to the longitudinal axis of the workpiece. This results in a particularly favorable arrangement of the optical elements of the optical system, in order on the one hand to generate a distortion-free silhouette of the workpiece, and on the other hand there is a structurally particularly compact arrangement in order to be adapted in an inspection system for checking a large number of workpieces on a holding device . Said plane of the optical elements can in particular be arranged at least essentially parallel or parallel to the main plane of a holding plate of the holding device, with the workpieces being held on this holding plate during the inspection.

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

Generally of independent importance, preferably generally within the scope of the invention, at least part of the optical elements arranged in the direction of the beam path in front of the workpiece is preferably designed as a beam path splitter, which divides the light beam of the lighting device into at least two partial beams, with a first partial beam being divided by means of the beam path splitter deflected in the direction of a first workpiece and a second partial beam in the direction of a second workpiece or. is aligned . The said beam path splitter is here preferably an optical element which directs the illuminating light directly onto the workpiece in order to produce a shadow image of the workpiece. The first and/or the second partial beam can be aligned directly with the respective workpiece in order to produce a shadow image of the same. The two partial beams preferably lie in a plane which corresponds to the plane of the optical elements described above, which is arranged at least essentially perpendicularly or perpendicularly to the longitudinal axis of the workpiece. In this case, the beam path splitter is preferably the optical element which is arranged in front of the respective workpiece in the direction of the beam path. The beam path splitter is particularly preferably a part of the light deflection device described above, in particular a part of the same that is arranged in front of the workpiece in the irradiation direction and/or in the direction of movement of the holding device of the workpieces through the optical system, with the beam path splitter preferably immediately in front of the said beam path direction and/or direction of movement Workpiece arranged. With the advantages of the beam path splitter in terms of equipment, the optical system is also structurally particularly simple as a result, with less effort for adjusting the optical elements and fewer possible optical imaging errors, due to the multiple functions of the beam path splitter.

The workpieces are preferably arranged on the holding device in a plurality of rows spaced laterally from one another. The at least two partial beams generated by the beam path splitter, which are directed onto the workpiece to create a shadow image, can be aligned on at least two workpieces in the same row or on workpieces in different rows of the row arrangement of the workpieces. The beam splitter particularly preferably generates exactly two partial beams, which are aligned with exactly two different workpieces.

The beam path splitter is preferably formed by two or possibly more plane mirrors, which are set at an angle to one another, preferably at an angle of h 20 and or 145°, preferably an angle h 30°, preferably

90° or 60°, particularly preferably approx. 45° or approx. 120°. The beam-dividing optical surfaces of the beam path splitter are preferably each designed as plane mirrors, with the optical surfaces being able to collide at an edge which preferably faces the illumination device. The beam path splitter can be arranged symmetrically in the beam path, so that the illuminating light incident on it is divided into two partial beams of the same illuminance or Luminous intensity is shared. The direction of incidence of the illumination light on the beam path splitter is preferably aligned with the bisecting line of the optical surfaces of the beam path splitter which are set at an angle to one another. If necessary, the beam path splitter can also generate more than two partial beams, preferably with the same illuminance or luminous intensity .

The optical system preferably comprises a plurality of mirrors in the beam path upstream of the workpiece, which are distributed around the circumference of the workpiece and which each produce a shadow image of the workpiece. These mirrors are each preferably designed as plane mirrors, preferably all of the mirrors that produce a shadow image of the workpiece. The mirrors that produce a shadow image of the workpiece are preferably arranged directly in front of the workpiece in the direction of the beam path, so that the light diverted or light projected directly onto the workpiece generates the respective shadow image. The mirrors are preferably spaced apart from one another in the circumferential direction of the workpiece, which is preferably arranged perpendicular to the longitudinal axis of the workpiece, in such a way that each mirror generates a shadow image that is spaced from an adjacent shadow image in the circumferential direction of the workpiece. The individual shadow images generated by the mirrors are thus each separated from one another in the direction of the circumference of the workpiece. However, the peripheral areas of the workpiece shown on the adjacent shadow images can overlap with one another. Each of these silhouettes is then gang direction behind the workpiece arranged light deflection devices on the optical detection means deflected or. projected . As a result, the detection means receives a plurality of separate shadow images of the respective workpiece, each shadow image corresponding to a peripheral portion of the workpiece. This enables a detailed inspection of the circumference of the workpiece with high precision. It goes without saying that the mirrors can be arranged in the workpiece peripheral direction in such a way that the shadow images, preferably of shadow images projected and detected adjacent to one another on the detection means, depict overlapping peripheral regions of the workpiece. As a result, a continuous peripheral area of the workpiece can be imaged on the detection means via several shadow images, which allows a particularly precise inspection of the workpiece. The plurality of mirrors can be arranged along an arc, e.g. of a circle section can be arranged around the workpiece, the arc or circle section extending, for example, over h 60° or h 90°, preferably h 120° or h 145° or up to approx. 180 ° or if necessary . extends more around the workpiece in order to be able to image a large peripheral area of the workpiece over several shadow images on the detection means. Except for the track of the workpiece as it moves through the optical system, the mirrors can be arranged approximately in a semicircle around the workpiece, but also in other ways. Here, 2, 3, 4 or more, for example. 5, 6 or more mirrors, in particular plane mirrors, which direct light onto the given workpiece to generate shadow images, may be provided.

Preferably, the optical system has a plurality of mirrors in the beam path between the workpiece and the optical detection means, preferably plane mirrors, which are distributed around the circumference of the workpiece, with at least one or more of these mirrors, preferably exactly one, each one of the A plurality of mirrors generating a shadow image are assigned and the shadow image generated by the respective mirrors arranged in front of the workpiece in the direction of the beam path is fed to the detection means. As a result, from the detection means several, preferably several separate, shadow images are captured. The mirrors that produce a shadow image and the mirrors downstream of the workpiece in the beam path each surround the workpiece, preferably partially, so that in each case there are preferably at least two or more mirrors distributed in the circumferential direction of the workpiece, each preferably in the form of a plane mirror.

On the lighting side of the workpiece, i.e. between the lighting device and the workpiece, a (first) plane mirror is preferably provided, which transmits the light emitted by the light source assigned to the workpiece for generating the shadow image, preferably directly onto a plurality of mirrors distributed around the circumference of a workpiece, preferably plane mirrors, which are preferably in Beam path direction are arranged immediately in front of the workpiece and generate a shadow image of the workpiece, aligns or. redirects . This gives a structurally particularly simple design of the optical system of the inspection system, which on the one hand due to the arrangement of plane mirrors or low-distortion. generates a substantially distortion-free image of the workpiece, and on the other hand due to the plurality of mirrors, which are arranged directly in front of the workpiece and each generate the same silhouette, a relatively large peripheral area of the workpiece can be inspected. Furthermore, because of the (first) plane mirror arranged on the illumination side, preferably only one light source can be used to generate a plurality of shadow images of the respective workpiece. For this purpose, the illumination device irradiates an area F1 of the first plane mirror, which is equal to or larger than the sum of the illumination areas of the several mirrors arranged directly around the workpiece, so that the plurality of shadow images can be generated by just one illumination device. The plurality of (second) mirrors that produce a shadow image of the workpiece can be arranged in a plane that is at least essentially perpendicular or perpendicular to the longitudinal axis of the workpiece. The first plane mirror can be arranged outside of this plane of the second mirror. Alternatively or additionally, it is on the detection means side a plane mirror is provided for the workpiece, which of several or all of the mirrors distributed around the circumference of a workpiece, which preferably each receive a shadow image directly from the workpiece, project the shadow images from this plurality of mirrors towards the detection means. The plurality of 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 in the direction of the plane mirror. The plane mirror thus preferably captures several or all of these shadow images of the plurality of mirrors at the same time and projects them preferably at the same time in the direction of the capturing means. This is beneficial in order to achieve projection of the shadow images towards the detection means with as little or no distortion as possible.

Generally within the scope of the invention, when the inspection process of the respective workpiece is carried out, the mirrors, beam path splitters and/or light deflection devices mentioned are preferably arranged in a stationary manner in relation to one another. This includes, of course, that the optical elements are preferably adjustable at their respective locations in the beam path.

In combination with the configurations of the inspection system described according to the invention or independently of these, the object is achieved by providing an inspection system according to claims 17 and/or 19 .

According to the invention, an inspection system is provided according to the preamble of claim 1 or generally according to the present invention, in which according to claim 17 the holding device has at least two rows of holders spaced apart from one another, each for at least one or exactly one workpiece, with between the workpiece and the optical detection means a light deflection device is provided, which in each case generates a shadow image of at least two workpieces from different rows of workpieces and onto the optical detection means, ie onto a and the same detection means . The detection means, which here detects the shadow images of workpieces in several rows, is preferably a structural and/or functional unit, such as preferably exactly one camera or exactly one sensor. Here, the detection means preferably has exactly one lens into which the shadow images of the two or more different shadow images of different rows of workpieces fall. This results in a structurally particularly simple design of the inspection system in order to be able to inspect a plurality of workpieces with little outlay on equipment, preferably being able to inspect them simultaneously. Only one detection means is therefore required in order to be able to inspect workpieces from a plurality of rows of workpieces. As a result, the inspection system can also be produced inexpensively, since the detection means, such as a camera, entails considerable costs. Furthermore, this design is particularly compact, so that a reliable inspection of the same is possible even when the large number of workpieces are arranged close together on the holding device.

The detection means is preferably designed to simultaneously detect the shadow images of workpieces in different rows. The optical system is preferably configured together with the workpiece arrangement in it and the detection means, so that several shadow images can be projected onto the detection means at the same time and can or can be detected by it at the same time. are recorded, which relates in particular to workpieces from different workpiece series.

The light deflection device is preferably arranged between the rows of workpieces, preferably between adjacent rows of workpieces, particularly preferably halfway between the respective rows of workpieces. The light deflection device can be arranged at the level of the workpieces with respect to a view perpendicular to the longitudinal axis of the workpiece. The same applies to a beam splitter, which can also be designed as a light deflection device. Generally within the scope of the invention, the holding device for the workpieces can be changed in position relative to the optical system of the inspection system. In this case, the optical system is preferably arranged in a stationary manner, particularly preferably all of its components, and the holding device is designed to be positionally variable, in particular with a translational change in position, particularly preferably with a linear movement. The holding device and thus also the rows of workpieces arranged on it can thus be positioned relative to the optical system and thus also relative to the above-mentioned light deflection device and/or beam splitter between the rows of workpieces on the optical system or be moved past the deflection device. As a result, the holding device can be part of a transport device for the workpieces, which feeds the workpieces from the device forming the workpieces, such as in particular an injection molding machine, past the inspection system to other devices on a workpiece production line, such as a handling device for removing defective workpieces, a packaging machine or the like. The transport device can extend continuously over the entire length of the production line. The inspection system is thus preferably part of an automated workpiece production and/or packaging line. The individual devices are preferably part of a coherent workpiece production line, with the workpieces, preferably arranged on a holding device and/or a carrier, being transferred directly from one device to the next within the production line, preferably without intermediate storage in a separate intermediate storage facility.

Furthermore, the object is achieved independently according to the invention or particularly preferably in combination with other configurations of the inspection system according to the invention by an inspection system according to claim 19, in which the holding device has at least two rows of holders spaced apart from one another, each for at least one or exactly one workpiece, with between the lighting device or light source and the tool piece a beam path splitter is provided, which splits the illuminating light and preferably simultaneously aligns it with workpieces from different rows of workpieces. This configuration is particularly advantageous in combination with the inspection system according to claim 17 and the developments thereof. As a result, the number of light sources required to inspect workpieces in several rows is significantly reduced. By means of only one light source, for example, at least two or optionally more rows of workpieces can thus be inspected by means of the inspection system according to the invention. The light source for the various rows of workpieces is preferably a structural and/or functional unit. The light source can have exactly one illuminant. The light source preferably has exactly one optics or Objective on which / s preferably produces exactly one beam of light. The light source is preferably stationary or arranged in an unchanged position in relation to the optical system of the inspection device and/or in relation to the detection means or devices that catch the respective shadow images.

In this case, the beam path splitter is preferably arranged at the level of the workpieces, when viewed perpendicularly to the longitudinal axis of the workpiece, so that the workpieces or Workpiece rows are guided past the side of the beam path splitter when the position of the holding device changes relative to the inspection system. At the same time, this results in a particularly compact design of the inspection system.

If the holding device has at least two or more spaced rows of holders for at least one or exactly one workpiece per holder, the detection means and/or at least one light deflection device, which transmits light from the lighting device or aligns from a light source to different rows of workpieces, and / or a light deflection device, which light from the workpiece or. deflects the workpiece silhouette towards the detection means, arranged between the rows of workpieces, preferably centrally between said rows of workpieces. This is a compact and structurally particularly simple and structurally compact design of the optical system or. of the inspection system as a whole. At least two spaced, preferably adjacent rows of workpieces can thus also be inspected using only one light source and/or only one detection means, which also reduces the outlay on equipment. The same also applies to a preferred arrangement of a beam path splitter, which splits the beam path from a light source and aligns or directs at least two partial beams to different rows of workpieces. projected .

The respective light source of the illumination device is preferably a point source. In this case, the point source preferably has a uniform light exit opening which extends over a continuous surface and which emits the light from the light source towards the optical system. The lighting device preferably has a constant luminous intensity over the extent of the point source. This includes the fact that the extent of the point source is preferably at least equal to or greater than the workpiece diameter at the longitudinal section of the workpiece examined by means of the inspection system. It is also preferred that the point source has a light exit surface whose width or Diameter has the distance between the rows of workpieces, the different rows of workpieces being illuminated by one and the same lighting device to produce shadow images of the respective workpiece. The distance between the rows of workpieces also includes the extension of the workpieces in their width on the side opposite the respectively adjacent row of workpieces. Said rows of workpieces are preferably arranged adjacent to one another. Said rows of workpieces are preferably formed in a straight line. It is generally understood that the holders of the holding device are each equipped with at least one or exactly one workpiece when the workpieces are inspected by means of the inspection system. Said point source is to be distinguished in particular from a ring-shaped light source, the central area of which does not emit any light in the direction of one or more workpieces to be examined.

According to a first generally preferred variant within the scope 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 results in a structurally simple arrangement of the lighting device and/or detection means and a shadow image of the respective workpiece can be generated in a simple manner. Furthermore, this makes it easy to adjust the optical system. For the simultaneous inspection of several workpieces held on the holder, the light sources and detection means for inspecting several workpieces can easily be arranged in a common housing, for example arranged next to one another. The housing preferably includes all light sources and detection means which are to be arranged next to one another in a plurality of rows of workpieces for the inspection of the workpieces on a holding device.

According to a second variant that is generally preferred within the scope of the invention, the light source and detection means assigned to the respective workpiece can be arranged in such a way that the beam path from the light source to the workpiece and on the other hand from the workpiece to the detection means are aligned coaxially at least over a partial length of the beam path. The light source and the detection means can be spatially aligned with one another in such a way that the light emitted directly by the lighting device is arranged at least approximately perpendicularly or perpendicularly to the light beam which enters the detection means. This results in a particularly compact design for specific applications.

According to the first and the second variant, the versions apply to all light sources and/or detection means of the inspection system. Generally within the scope of the invention, “assigned to the workpiece” is understood to mean a light source which generates a shadow image of the respective workpiece.

The optical system preferably has an optical element which is designed to be partially transparent and which is visible both in the beam path of the light or Arranged in the beam path and at the same time in the light falling from the workpiece in the direction of the detection means. This optical element is preferably designed as a plane mirror. The optical element which is preferably aligned obliquely to the beam path of the incident light beam from the illumination device and obliquely to the direction of the light beam directed from the workpiece to the detection means, preferably in each case at an angle of approx. 45° to the respective light beam. The optical element thus has, on the one hand, reflective properties in relation to the illumination light and, on the one hand, transparency in relation to the light guided towards the detection means. Said optical element can have a suitable coating for this purpose, for example, as is customary in the case of partially transparent mirrors, for example. The light incident on this optical element on the lighting side and the light passing through to the detection means can fall on the same area of the optical element. This allows flexible arrangement of the lighting device in relation to the research device, which is also designed to be compact and space-saving.

According to a preferred embodiment, the optical system is designed in such a way that the workpiece to be examined is preferably irradiated simultaneously with at least two separate partial beams from at least one, preferably exactly one, light source in order to produce a different shadow image of the respective workpiece with each partial beam. Point the separate sub-beams between the workpiece in its inspection position and the detection means, which for the at least two partial beams is preferably the same detection means as a camera or a sensor, have different beam path lengths, 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 improves the image sharpness of the different shadow images in the detection means are adjusted to each other. This optical element is referred to here as an "adaptation element". The beam path length of the partial beam paths can be regarded as the geometric length of the same. Due to the given depth of field of the optics or the lens of the detection means, in particular a given focal length of the same, there is the problem that Objects can appear differently sharp at different distances from the detection means. The lens is preferably set sharply on the workpiece in relation to a partial beam path, so that the shadow images of one workpiece produced by other partial beams can appear blurred. The at least one optical adjustment element in the sharpness of the various shadow images is thus adapted to one another in the partial beam paths, so that preferably all shadow images appear sharp or equally sharp, regardless of the length of the beam path of the respective partial beam path, and the inspection of workpieces from different rows can thus be carried out with the reliability. On the other hand, this makes it possible for shadow images to be generated from different directions of the given workpiece and for the optical system and/or light source and/or detection means to be adapted in a variety of ways to special requirements such as geometry of the workpiece, spatial conditions on the inspection system or the like . The optical adjustment element is preferably arranged in a partial beam path which has a greater or the greatest beam path length of the various partial beams which produce shadow images of one workpiece. Such an optical element can preferably be missing in the partial beam path with the shortest beam path length. The adjustment element is preferably designed as a refractive optical element, in particular as one or more prisms, one or more plano-optical elements such as planar plates with planar, mutually parallel light entry and light exit surfaces, or combinations thereof. The partial beams preferably fall perpendicularly onto an optical surface of the optical element, such as a light entry surface of the same. The partial beams preferably exit perpendicular to the optical exit surface of the optical element. The partial beams preferably impinge on the optical adjustment element as a bundle of parallel light beams. The partial beams are preferably radiated or emitted as a bundle of parallel light beams from the adjustment element in the direction of the detection means. diverted . According to a preferred variant, the adjustment element is designed as a 60°-120° prism, preferably as a 90° prism. One or more adjustment elements, in particular in the form of a prism, can be arranged directly in front of an optical deflection element, preferably in the form of a deflection mirror, of the optical system. The deflection element is preferably arranged obliquely to the longitudinal axis of the workpiece in its examination position in order to deflect the beam path out of a plane that is at least essentially perpendicular to the longitudinal axis of the workpiece and to direct it to the detection means, which is preferably arranged outside of this plane. This results in a structurally particularly compact design. The at least one adjustment element and the deflection means, in particular as a plane mirror, can be designed as a structural unit, which facilitates the assembly and adjustment of the optical system. The adjustment element can also only extend over a first part of the optical surface of the deflection element, with at least one other partial beam, which represents a different silhouette of one of the workpieces, being directed onto the other d. H . second part of the optical surface of the deflection element falls and from this to or. is diverted to the same detection means.

If necessary, the adjustment element can also have at least one or several mirrors, for example also simulation games, which can also be arranged directly one behind the other in the direction of the beam path. The design of the adjustment element as a light-refracting optical element is preferred because of its particularly compact design.

In general, the optical system preferably has no optical elements with convexly or concavely curved optical surfaces, such as lenses and/or concave mirrors with curved mirror surfaces. The optical system preferably has no light-diffracting optical elements. Any lens of the respective detection means and/or any lens of the respective light source are generally not to be regarded as part of the optical system.

According to one embodiment, all optical elements of the optical system are preferably plane mirrors, except for any optical elements that adjust 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.

All optical elements of the optical system are preferably stationary to the lighting device or. Light source and / or arranged the detection means.

In general, within the scope of the invention, the inspection system can be designed in such a way that it inspects a plurality of partial areas of the workpiece that are spaced apart from one another in the longitudinal direction of the workpiece. For this purpose, the respective workpiece can, for example, pass through two independent inspection systems which are arranged one behind the other in the transport direction of the holding device and which in each case inspect different sections of the workpiece. If the transport speed of the holding device is known, the shadow images generated in the two inspection systems can each be assigned to a specific workpiece, so that its geometry or Material defects can be inspected more precisely. The concentricity of the workpiece can also be determined or be calculated by means of the evaluation device. 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 purpose, for example, a separate lighting device can be provided for each area to be inspected in the longitudinal direction of the workpiece, with the optical system being designed in such a way that the shadow images of the two workpiece sections that are spaced apart in the longitudinal direction of the workpiece are detected using the same detection means.

The invention also includes an inspection method for checking elongated workpieces using an inspection system according to the invention. Statements on the inspection procedure also apply accordingly to the inspection system and vice versa.

According to a preferred embodiment of the inspection method, the holding device for holding at least one or a large number of workpieces to be checked is moved relative to the optical system in order to move the workpiece to be checked from a non-examination position to an examination position on the optical system that produces the shadow image of the workpiece transfer, wherein the exposure time of the workpiece to generate the at least one shadow image is less than / equal to 1 millisecond, preferably 250 microseconds or 100 microseconds or 50 microseconds . This is made possible by the high contrast of the workpiece image in the form of a silhouette. The light source can be operated intermittently, i.e. clocked, or continuously to illuminate the workpiece. In general, with electronic image acquisition and processing, the exposure time can be the length of time within which shadow images or corresponding image information is accumulated to generate the silhouette to be evaluated. The exposure time can be equal to or shorter than the length of time the workpiece is in its inspection position. The transport speed of the workpiece or of the holder by the optical system can be h 50 mm/sec or h 100 mm/sec or h 250 mm/sec, if necessary. also h 500 mm/sec .

The invention is explained below by way of example using a number of exemplary embodiments. It goes without saying that various features of the respective exemplary embodiment can also be combined with features of other exemplary embodiments. All features of the exemplary 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 with lighting devices, the optical system and an optical detection means with workpieces in a perspective view ( FIG. 2A ) and in a plan view ( FIG. 2B ) and in a modified embodiment ( FIG. 2C ) ;

Fig. 3: a second embodiment of the invention

Inspection system with lighting device, detection means and optical system with several rows of workpieces;

Fig. 4: a third embodiment of the invention

Inspection system with lighting device, detection means and optical system with a plurality of 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. 4 with several optical systems arranged side by side and detection means for inspecting a plurality of rows of workpieces;

Fig. 6: an illustration of the detection means of the inspection system according to FIG. 4 captured several shadow images of a workpiece;

Fig. 7: a further alternative of the inspection system with lighting means, optical system and detection means;

Fig. 7: another alternative of an 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 a beam path splitter or light deflection device according to a first embodiment (FIG. 8a) and a second embodiment (FIG. 8b).

Figures 1 to 5 and 7, 8 show embodiments of inspection systems according to the invention or. parts of the same. FIGS. 2, 3, 4 and 7 show inspection systems with an arrangement of several workpieces arranged on the holding device in rows of workpieces. The holding device is not shown in each case or is only indicated schematically; a holding device according to FIG. 1 or another suitable holding device can be used.

Fig. 1 shows a perspective representation of a holding device 3 for an inspection system 1 according to the invention, wherein this holding device 3 can be provided on all exemplary embodiments of the inspection system 1 or generally within the scope of the invention.

The holding device 3 has a multiplicity of holders 3a, wherein at least one or in particular precisely one workpiece 2 is or can be held on each of the holders 3a. The workpiece 2 can, for example, by negative pressure on the respective Holder 3a be held or by a mechanical device or in any other suitable way. The large number of workpieces is here fixed in a defined spatial position to one another on the holder, for which purpose the workpieces 2 are arranged here with their workpiece longitudinal axes 2a (FIG. 2a) coaxially to one another. 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 transverse to this direction. The arrangement of the workpieces 2 on the holding device 3 can correspond to the arrangement of the workpieces as is present in a shaping device such as an injection molding machine with a large number of cavities for the simultaneous production of injection molded parts. The holding device 3 can be changed in position compared to the other devices of the inspection system, such as in particular an illumination device 4 , an optical system 5 and an optical detection means 6 (see e.g. Fig. 2 ), so that the workpieces arranged on the holding device 3 can be changed by changing the position of the holding device are transported through the optical system 5, in particular in a translational movement, in particular a linear translational movement (arrow direction), in order to be able to check the workpieces 2 by means of the optical detection means 6, such as a camera, with regard to workpiece defects. The holders 3a are here arranged on a flat holding plate 3b. It goes without saying that, in general, the holding device can also be designed in a different way, in particular the multiplicity of workpieces 2 can be arranged in a different spatial arrangement relative to one another on the holding device. The rows or Traces of workpieces are arranged here in a straight line and aligned parallel to one another, but this is not absolutely necessary, for example the workpieces 2 can also be arranged in a pattern on the holding device, preferably corresponding to the structure of the shaping tool or the injection molding cavity of an injection molding machine. At the holding device 3 in FIG. 1, eight rows each with eight workpieces are held, without being limited to this. The holding device 3 is in this case Longitudinally according to the direction of the arrow by the inspection system according to the invention, which can be part of an automated production plant, transported and thus also moved in the longitudinal direction by the optical system of the inspection system. If necessary, this can of course also be done in a direction transverse to the longitudinal extension of the holding device. The transport speed of the holder 1 through the optical system of the inspection system can be in the range from 250 mm to 1000 mm/sec or more.

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

The inspection system 1 has a holding device 3 for holding at least one or a large number of workpieces to be inspected, the holding device according to FIG. 1 can be formed. The workpieces can be arranged in several rows R separated from one another by a distance d (see FIG. 1), the rows preferably being formed in a straight line as here, but generally also in a different arrangement.

The inspection system 1 includes an illumination device 4 with at least one light source 4a. If several rows of workpieces are provided, then several light sources can also be provided in order to emit light onto the workpieces for inspection, which can be constructed in the same way. The light source is designed here as a point source, possibly but can also be designed in a different way, in which case the respective light source can have a constant light intensity over its entire light emission surface. The diameter of the light source 4a is dimensioned in such a way that it irradiates the optical elements of the optical system 5 described below sufficiently and preferably more than they are relevant in relation to the workpiece inspection, preferably with a uniform light intensity. According to the exemplary embodiment, the lighting device 4 comprises a plurality of light sources 4a, which are arranged next to one another here, but also one can have different spatial assignments or distances from one another. Due to the special design of the optical system 5 , as described below, the number of light sources 4a is smaller than the number of rows of workpieces on the holding device 3 . More precisely, here the light sources 4a are arranged halfway between the workpiece rows R, preferably between adjacent rows which have a greater distance d than other adjacent rows. On the rows delimiting the field of workpieces, a further light source 4a is provided in each case on the side facing away from the field of workpieces. For a total of eight rows of workpieces R in a holding device 3 according to FIG. 1 five light sources 4a are therefore provided. It goes without saying that, depending on the design of the inspection system according to the invention, a separate light source 4a can also be assigned to each row of workpieces. Furthermore, it goes without saying that the inspection system can also be used in each case to check only a single workpiece or only two or more workpieces arranged next to one another.

Furthermore, the inspection system 1 comprises an optical system 5 for aligning the light emitted by the light source 4a preferably laterally onto the workpiece 2 to be inspected arranged on the holding device 3 . The light emitted is in each case preferably in the visible range (380-780 nm), as is generally the case within the scope of the invention, without being restricted thereto. The workpiece 2 to be checked is thus in its examination or measuring position on the inspection device, as shown in FIG. 2 and the other figures for the workpiece covered by the illustrated beam path.

The light radiated from the respective light source 4a onto the workpiece 2 to be examined is incident here at an angle of 45° to 135°, preferably 60° to 120° or 75° to 105°, according to the exemplary embodiment at an angle of 90° the workpiece longitudinal axis 2a in order to be able to check that the workpiece 2 is free of defects. The optical system 5 directs the light from the light source 4a essentially or exactly perpendicular to the workpiece longitudinal axis 2a on the workpiece.

The optical system 5 is designed in such a way that it irradiates the workpiece 2 to generate its shadow image 73 (FIG. 6) and projects the shadow image onto the detection means. The light rays incident on the workpiece are aligned at least substantially parallel or parallel to one another. The light source 4a or All light sources of the lighting device 4 emit light bundles with at least essentially parallel or parallel light beams. The optical system 5 is designed such that the light beams of the workpiece silhouette impinge on the optical detection means 6 as a bundle of at least substantially parallel or parallel light beams. The optical system 5 is preferably designed in such a way that the shadow image generated is at least essentially undistorted and that the shadow image falls on the detection means at least essentially undistorted or undistorted. The exposure time of the workpiece can be less than 10 microseconds.

Furthermore, an optical detection means 6 (generally abbreviated: "detection means") is provided, the workpiece 2 being arranged in the beam path S of the light emitted by the light source between the light source 4a and the optical detection means 6 and the optical detection means being generated by the illumination captures an image of the workpiece 2. The detection means 6 is designed here as a camera, but can also be designed as an image sensor or in some other suitable way, with cameras being particularly preferred in order to record the respective shadow image undistorted and then to send it to image processing.

An evaluation device 7 is preferably also provided, which is connected to the optical detection means 6 in a signal-transmitting manner. The evaluation device 7 is configured to compare the detected by the optical detection means To enable or carry out a workpiece image 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 recorded workpiece image with the reference. The evaluation by means of the evaluation device can be computer-aided, for example using electronic image processing, or in another suitable manner. In the simplest case, the workpiece image is shown on a display of the optical detection means for checking by a person.

The optical system 5 is particularly preferably designed here in such a way that it generates an undistorted shadow image of the workpiece 2 from at least one direction transverse to the longitudinal axis of the workpiece and projects the generated shadow image undistorted onto the optical detection means. “Undistorted”, also called “distortion-free”, includes here and generally within the scope of the invention at least essentially distortion-free or distortion-free. By generating the undistorted shadow image, the freedom from defects of the workpiece can be checked in a particularly reliable manner using simple equipment.

The optical system 5 has at least one plane mirror 5a, which the light source 4a, or. generally directs the light from the light source 4a associated with the respective workpiece onto the workpiece 2, here two such plane mirrors 5a, 5b, in order to produce shadow images of the workpiece that are as undistorted as possible. In relation to the beam path from the light source 4a to the workpiece 2, the at least one plane mirror 5a, here both plane mirrors 5a, 5b, is arranged directly in front of the workpiece. It goes without saying that, if necessary, more than two such plane mirrors, which direct light directly onto the workpiece, can be provided to generate shadow images of the same.

The shadow image produced is at least essentially undistorted or undistorted in relation to the workpiece. The light radiated from the plane mirrors 5a, 5b onto the workpiece 2 is gang direction behind the workpiece at least essentially undistorted or undistorted to the detection means 6 or redirected. projected and each recorded by this.

In addition to the at least one plane mirror 5a, 5b, according to the exemplary embodiment the at least two or more plane mirrors 5a, 5b, a deflection mirror 5u designed as a plane mirror is provided on the lighting side in the beam path, i.e. facing the lighting device in relation to the workpiece in the beam path. One of the plane mirrors 5a, 5b can also be designed as a beam path splitter, as described below. The deflection mirror 5u deflects the light from the light source 4a in the direction of the workpiece, with the light emission direction of the light source 4a being arranged at an angle to the light which falls on the workpiece to produce the shadow image. The light for generating the shadow image is directed onto the workpiece essentially or exactly perpendicularly to the longitudinal axis 2a of the workpiece by means of the deflection mirror 5u. The light source 4a emits the light at an angle other than at least substantially perpendicular to the longitudinal axis 2a of the workpiece, in this case coaxial to the longitudinal axis of the workpiece 12, in the direction of the workpiece 2. The deflection mirror 5u thus generally deflects the light emitted by the light source 4a into a plane which is arranged at least essentially perpendicularly or perpendicularly to the longitudinal axis 2a of the tool. The light is deflected here by 90°, for this purpose the deflection mirror 5u is arranged at an angle of 45° to the longitudinal axis 2a of the workpiece. By arranging at least one or more plane mirrors, which are arranged directly in front of the workpiece, here the plane mirrors 5a, 5b, and the deflection mirror 5u designed as a plane mirror, a distortion-free shadow image of the workpiece is generated. The optical system 5 in the beam path between the illumination device and the workpiece 2 here consists exclusively of plane mirrors.

Furthermore, the optical system 5 in the beam path between the workpiece 2 and the optical detection means 6 also has at least at least one or more plane mirrors, which are arranged one behind the other in the direction of the beam path, exclusively plane mirrors according to the exemplary embodiment. The feature of “optical elements arranged one behind the other in the beam path” relates here and generally within the scope of the invention to the propagation direction of the light.

The beam path S is telecentric on the objective side and/or on the image side. The lighting device thus has a telecentric light source, which thus emits light onto the workpiece with rays that are parallel to one another. Several or all of the optical elements of the optical system 5 between the lighting device and the workpiece and between the workpiece 2 and the detection means 6 are true to the image here, so that light rays that are incident in parallel are forwarded, in particular reflected, as parallel light rays in the direction of the detection means. In general, light-refracting and/or light-diffracting optical elements, such as lenses, in particular lens arrangements with a plurality of lenses arranged one behind the other as the optical element, and/or optical prisms and/or optical plates could also be used for this purpose. Preferably, no light-diffracting optical elements are provided. Refractive optical elements, in particular, to the effective length of different partial beam paths. However, the use of plane mirrors is particularly advantageous since they are structurally simple, represent inexpensive components and can be produced with high optical quality in order to produce a distortion-free silhouette of the tool and project it onto the detection means.

In the beam path S between the lighting device or At least one beam path splitter 5s is arranged at the light source 4a and the detection means 6 , more precisely in the beam path between the light source 4a and the workpiece 2 . The beam path splitter 5s splits the light emitted by a light source 4a of the illumination device into at least two, here exactly two, separate partial beams S1, S2 (FIG. 2b). The various partial beams Sl, S2 can be aligned, preferably simultaneously or with a time offset, on different workpieces 2, in particular those of different rows RI, R2, in order to generate shadow images of the same simultaneously or with a time offset. The rows R1 , R2 are here arranged in a straight line with a distance between them . The beam path splitter 5s is designed as a plane mirror or. has several plane mirrors and is more precisely composed of such. The beam path splitter 5s is arranged directly in front of the workpiece in the direction of the beam path, so that the light directed by it directly onto the workpiece generates a shadow image. If necessary, several such beam path splitters can also be provided, which, for example, align different partial beams onto several workpieces 2 . The partial beam paths SI, S2 and the optical elements arranged in them can be designed generally, as described for the beam path between the respective light source and the workpiece.

The beam path splitter 5s is arranged in a fixed position opposite the light source 4a and the other optical elements of the optical system, under certain circumstances a movable beam path splitter can also be used, which splits light from the light source 4a in different positions of its movement and in the direction of different rows R deflects, the workpieces of these rows being acted upon simultaneously or at different times by the respective light to produce a shadow image, which can generally apply within the scope of the invention.

The beam path splitter 5s, or generally another optical element, preferably in the form of a plane mirror, is arranged in the light emitted by the light source 4a in such a way that a partial beam Sla is hidden from the light beam and another partial beam Slb to another optical element , is preferably transmitted in the form of a plane mirror, with both or optionally more partial beams being radiated onto the workpiece 2 in order to produce a respective shadow image of the same. At the same time, the beam path splitter provides the plane mirror 5a for the given workpiece 2 . The optical elements arranged in the beam path S between the light source 4a and the workpiece 2 are arranged here in such a way that the shadow images of the respective workpiece generated by a plurality of partial beams Sla, Slb are detected separately from one another by the detection means 6 and can preferably be evaluated separately by the evaluation device. The evaluation can be carried out in such a way that concentricity of the workpiece can be checked. On Fig. 6 is referred to accordingly.

The two partial beams Sla and Slb are here in a direction of approx. 90° to each other towards the workpiece and impinge on the workpiece at this angle. The two partial beams Sla, Slb impinge on the workpiece 2 at least substantially perpendicularly or perpendicularly to the longitudinal axis 2a of the workpiece.

A light deflection device 51 of the optical system is provided in the direction of the beam path between the light source 4a and the workpiece 2, with at least a first part of the light deflection device 511 being located in front of the workpiece in relation to the irradiation direction of the light in the plane that is at least essentially perpendicular to the longitudinal axis 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 here to the direction of movement of the holding device through the optical system, corresponding to the direction of the arrow . The light deflection devices 511 and 512 are arranged here on different sides of a vertical of the straight workpiece row R and are thus positioned in front of and behind the workpiece. This light deflection device 51 is at least substantially perpendicular or light radiated perpendicularly to the longitudinal axis of the workpiece or Arranged light beam. Each of the two parts of the light deflection device 511, 512 deflects light directly onto the workpiece and generates a shadow image of the workpiece, in this case different shadow images from the two directions to the workpiece. piece . If necessary, more than two such light deflection devices can also be provided and/or the light deflection device can comprise more than two parts, so that more than two shadow images of one workpiece are generated. The respective shadow images of one workpiece 2 are each projected separately from one another onto the optical detection means 6 and are detected separately by it. The different shadow images of one workpiece, which are generated by the different parts of the light deflection device 51, can be detected by the detection means 6 at the same time, possibly also with a time offset, which can also apply generally within the scope of the invention. The beams directed onto the workpiece by the two parts of the light deflection device 511, 512, which produce separate shadow images of the workpiece, enclose an angle with one another, preferably an angle of h 30° and/or , and 120 ° , preferably approx .

90 degrees. With regard to the design of the light deflection device and the guidance of the beam path, reference is made to the above statements on the beam path splitter. The light deflection devices 511 and 512 are designed here as plane mirrors. In this case, the light deflection device 511 is at the same time part of the beam path splitter 5 s, but this is not mandatory. Here, the light deflection device 512 is not at the same time part of a beam path splitter, but can optionally be an alternative or additional part. The arrangement of the light deflection devices 511 and 512, which are in front of or are arranged behind the workpiece, the front side facing the light source and the back side of the workpiece facing away from the light source can thus be checked by generating shadow images. The light deflection devices 511, 512 or, if applicable, all of the light deflection devices provided, which align the light directly onto the workpiece to generate the shadow image, are designed as plane mirrors according to the exemplary embodiment.

Between the beams falling on the workpiece from at least two parts of the light deflection devices 51, here the parts 511, 512 , is an angle of h 30° and/or 175°, preferably h 145° and 35°, preferably b 60° and 120°, here approx. 90° intended. The perpendicular arranged to the row of workpieces represents at least approximately a bisector of said angle of the beams directed directly onto the workpiece by parts 511 , 512 of the light deflection device.

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 radiates light from the light source 4a directly onto the workpiece to form a shadow image of the same a corresponding part 5rl, 5r2 of a light deflection device 5r is assigned in the direction of the beam path between the workpiece and the optical detection means 6. This generally applies regardless of the arrangement of the parts of the light deflection device 51, ie z. B. in relation to the arrangement in front of or behind the workpiece, so 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 generated by the respective light source-side part 511 of the light deflection device 51 is projected onto the light deflection device 5rl and is deflected or deflected by the latter in the direction of the detection means 6. projected . The silhouette generated by the light deflection device part 512 is deflected or deflected onto the optical detection means via the corresponding light deflection device part 5r2. projected . The parts 511 and 512 and the parts 5rl and 5r2 are designed here as separate parts. The parts 5rl, 5r2 are each designed as plane mirrors. As a result, different shadow images of one and the same workpiece are presented to the optical detection means 6, here from different views or Irradiation directions of a workpiece supplied.

The light deflection device 5rl is part of an optical element 5v, which has two plane mirrors set at an angle to one another, i.e. in addition to the plane mirror 5rl a further ren plane mirror 5vl . The light deflection device 5v is structurally constructed here like a beam path splitter 5s, so that reference is made to the explanations in this regard. However, the edge of the light deflection device 5v, in which the plane mirrors 5rl, 5vl converge or abut one another, faces the detection means 6. In this case, the optical element 5v directs the light beams from workpieces of different workpiece rows RI, R2 here to the one common detection means 6, which takes place 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 5rl, 5vl, is thus in the beam path between at least one light source, here two light sources, and two workpieces, preferably workpieces from different rows, and one--i.e. a common--detection means 6, which captures the shadow images which detects at least two workpieces from different rows RI, R2 and preferably forwards them to the evaluation device 7 in a signal-transmitting manner. The optical element 5v thus combines the shadow images of different workpieces 2 of different rows RI, R2. The detection means here detects the shadow images of the workpieces 2, 2' of different rows RI, R2 simultaneously, since the workpieces 2, 2' with respect to the passage through the optical system or are arranged on the holding device 3 at the same height. Are the workpieces 2, 2' in relation to the passage through the optical system or arranged on the holding device 3 at different heights, i.e. not one behind the other but offset from one another when viewed from the side, the detection means detects the workpieces 2, 2' of different rows RI, R2 at different times, with the respective workpiece however, nothing changes in the beam path.

Furthermore, a light deflection device 5n is provided in order to deflect the generated shadow images of the respective workpiece in the direction of the optical detection means 6, here for example a camera. The deflection takes place here by reflection. The direction of incidence of light in the detection means 6 is here at an angle, here perpendicular, to the plane E in which the shadow images are generated. The light diverter 5n is here also arranged at 45° to the plane E and/or to the direction of incidence of light in the optical detection means 6 . The light deflection device 5n is designed here as a plane mirror. The light deflection device 5n directs several or all of the partial beams Sla, Slb, which correspond to individual shadow images of one workpiece, onto the detection means 6. The detection means 6 is arranged here outside of the plane E perpendicular to the longitudinal axis of the workpiece. In general, within the scope of the invention, however, multiple light deflection devices 5n can also be provided, if necessary, in order to direct the multiple shadow images of a workpiece onto the detection means. This can also apply generally within the scope of the invention.

The light deflection device 5n deflects partial beams SI, S2 of different workpieces 2, which are arranged here in different rows RI, R2, onto the detection means 6, which can apply independently of or in addition to the deflection of the different partial beams Sla, Slb in relation to a specific workpiece or . additionally applies here. This can also apply generally within the scope of the invention.

The optical elements 511, 512, 5s, which radiate light directly onto the workpiece to generate at least one or more shadow images of the workpiece, are arranged in such a way that the light and thus also the shadow image are generated by a central workpiece section, based on the longitudinal direction of the workpiece , optionally alternatively or additionally , for example , also 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.

In the inspection system according to FIG. 2 the workpieces 2 are arranged in laterally spaced rows RI, R2. The holding device 3 is designed here, for example, as shown in FIG. 1 , or in any other suitable manner . Of the several rows of workpieces of the holding device, according to FIG. 1 eight such rows are shown in FIG. 2 shows only two such rows. the The holding device 3 can change its position relative to the optical system 5, in particular translationally, so that when the holding device is displaced relative to the optical system 5, the workpieces are guided through the optical system 5 along the longitudinal extent of the rows R. In this case, the holding device can be moved continuously, so that the workpieces continuously pass through the optical system; if necessary, a step-by-step movement of the holding device is also possible. As a result, one of the workpieces of the respective row R enters the examination area of the optical system 5 one after the other, as is the case for the two in FIG. 2 rows shown for each one workpiece (with a corresponding beam path) is shown. In the examination position of the workpiece shown, the partial beams Sla, Slb of the light deflection devices 511, 512 intersect. It goes without saying, however, that - also generally within the scope of the invention - the respective workpiece can also pass through examination or measurement positions that are spaced apart from one another in the direction of movement of the holding device, with shadow images from different directions and/or from different longitudinal sections of one and the same workpiece are generated, which can be evaluated individually or together in the evaluation device 7. The respective light source 4a, which is therefore assigned to a workpiece or a row of workpieces for generating a shadow image of the respective workpiece, is arranged here between adjacent rows R1, R2, preferably in the middle between them. This also applies here to the beam path splitter 5s and the light deflection device 5n, and on the opposite side of the given workpiece or the row of workpieces for the light deflection devices 5rl, 5rl, 5v and the detection means 6. In order to also be able to detect the rows of workpieces laterally delimiting the field of workpieces, two further light sources 4a with associated beam path splitters 5s are provided at the lateral boundaries of the field, so that only five light sources 4a with associated beam path splitters 5s are provided for the eight rows of workpieces. Furthermore, in the arrangement described, the holding device 3 is spaced apart by more than two or more than 3 Rows of holders for each at least or exactly one workpiece, between the workpiece and the detection means 6 a light deflection device 5n is provided, which aligns the shadow images of two workpieces of different workpiece rows R on a detection means 6. The shadow images of the two workpieces in the different rows can preferably be captured simultaneously by a detection means, or possibly also in chronological succession, in particular if the workpieces in different rows have reached the examination position of the optical system for generating the shadow image(s) of the respective workpiece at a different run through time . As a result, only one optical detection means 6 is required for two rows of workpieces R, here two adjacent rows of workpieces RI, R2, which is particularly cost-effective and saves installation space, particularly in the case of rows of workpieces standing close together. For the eight rows of workpieces with a holder according to FIG. 1 are thus only four optical detection means 6 such as. cameras required. It goes without saying 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 means 6 could be used here - which, in view of the higher costs of the detection means compared to the light source but is less beneficial.

The light sources 4a of the lighting device are each designed as a point source, which has a uniform light intensity over its entire emission surface. The diameter of the light source is dimensioned in such a way that the beam path splitter 5s or are each irradiated in accordance with a first light deflection device 511 and a second light deflection device 512 in order to generate corresponding shadow images. The light sources here emit light bundles with light beams that are parallel to one another.

Fig. 2c shows a modification of the inspection system according to FIG. 2a, b, for the rest, reference is made to the statements made there. The optical system is designed in such a way that the workpiece 2 to be examined is irradiated, here simultaneously, with two separate partial beams Sla, Slb of a light source 4 in order to produce a different shadow image of the respective workpiece with each partial beam Sla, Slb. The separate partial beams Sla , Slb for the same workpiece are detected by a common detection means 6 . The separate partial beams Sla, Slb between the workpiece in its examination position, as shown in FIG. 2 b , and the detection means 6 have a different beam path length between the workpiece 2 and the detection means 6 in each case, then in this section the beam path of the partial beam Slb is longer than the partial beam Sla. With a larger difference in the partial beam lengths, as in FIG. 2 c, the two shadow images could appear with different sharpness given the depth of focus of the detection means lens. In one of the beam paths of the partial beams Sla, Slb between the workpiece and the detection means, here in the longer partial beam Slb, an optical element 5x1 (dashed) is therefore arranged here as an adjustment element, which adjusts the image sharpness of the various shadow images in the detection means to one another or corrected to equal sharpness. The optical element 5x1 is designed here as a prism. The partial beam Slb falls perpendicularly onto the light entry surface of the prism and leaves the prism perpendicularly to the light exit surface of the same. The prism here is a 90° prism, the light entry and light exit surfaces are perpendicular to one another. The optical element 5x1 is arranged directly, ie in general preferably without a gap, on the light deflecting element, here the plane mirror 5n, for example permanently attached to it. No such adjustment element is arranged in partial beam path S1a (not shown in FIG. 2c), whereby generally with a suitable design of the adjustment elements, adaptation elements can also be provided in all partial beam paths for one workpiece. Since two light beams SI, S2 from 2 different workpieces in different rows fall on the light deflecting element 5n, which come from two different light sources here, there is also a second beam path for the partial beam path S2b, which is longer than the partial beam path Sla optical adjustment element 5x2 provided. The matching elements 5x1 and 5x2 are constructed identically for the given beam path geometry, but this is not mandatory. The two adjustment elements 5x1, 5x2 are here on the two edge areas of the deflection device or Plane mirror 5n arranged. The shorter partial beams S1a, S2a fall directly onto the deflection element 5n in the intermediate space Z between them. The means of light deflection or. Plane mirror 5r2 in the direction of the detection means 6 radiated light thus falls on the respective adjustment element 5x, the means of light deflection or. The light emitted by the plane mirror 5rl in the direction of the detection means 6 falls into the intermediate space Z and thus directly onto the deflection mirror 5n.

Fig. 3 shows an alternative embodiment of the inspection system according to the invention. The differences from the exemplary embodiment according to FIG. 2 described, for the rest, the full content of the statements on the embodiment of FIG. 2 referenced. Components of the inspection system according to FIG. 3, which components of the embodiment of FIG. 2 are each provided with a reference number increased by "10". The inspection system according to FIG.

In the inspection system 11 according to FIG. 3 is each workpiece 12 or each row R of workpieces is assigned its own light source 14a of the lighting device 14 . The light emitted from the light source 14a is thus projected onto only one workpiece to produce a shadow image thereof. As a result, the silhouette can have a relatively large width, the light beam of one light source 14a can here cover the entire diameter of the workpiece.

Irradiate pieces. The light beams incident on the workpiece 12 from the light source 14a also fall here at least essentially perpendicularly or perpendicularly to the longitudinal axis 12a of the workpiece on the workpiece 12 . The light beams incident on the workpiece 12 are arranged in such a way that a central section of the workpiece 12 is illuminated to produce a shadow image; the free end or the bottom area of the workpiece can be illuminated to generate a shadow image, including, for example. the light beam can have a corresponding width, so that the silhouette also includes the floor area. The "free end" of the workpiece is understood here - as also generally within the scope of the invention - to be the workpiece end which is arranged facing away from the holding device 13 a beam path splitter are aligned, which generates at least two or more partial beams, each of which is aligned to different workpieces or to a workpiece from different directions.

The optical system 15 here has a light deflection device 15u, which is designed as a plane mirror and which directs the light emitted by the light source 14a onto the workpiece 12 in order to produce a shadow image of the same. Furthermore, a light deflection device 15n is provided behind the workpiece 12, i.e. on the side thereof facing away from the light source 14a, which directs the directly generated shadow image in the direction of an optical detection means 16 such as, for example, redirects a camera . The light deflected by the light deflection device 15u is emitted in a direction which is arranged in a plane with the light beam impinging directly on the workpiece, this plane E being arranged at least essentially perpendicular or perpendicular to the longitudinal axis 12a of the workpiece. By means of a further light deflection device 15n, here in the form of a plane mirror, the silhouette is then deflected in the direction of the detection means 6 or projected . By means of a deflection device or Plane mirrors 15n are used to deflect and project shadow images of workpieces in adjacent rows RI, R2 onto a common detection means. The light deflection device 15n pels the light incident into it out of the plane that is at least essentially perpendicular or perpendicular to the longitudinal axis of the workpiece, in the direction of the detection means 16 .

The generated shadow images of the workpieces of different, here adjacent, rows RI, R2 are projected by means of plane mirrors 15v1, 15v2 of the optical element 15v in the direction of the detection means 16 or projected, more precisely reflected, in the direction of or onto the light deflection device 15n. One detection means 16 detects the shadow images of different rows of workpieces, here at the same time or if necessary. also offset in time, depending on the temporal arrangement of the two workpieces 12 in their examination or Measuring position in the beam path. The optical surfaces Plane mirrors 15vl, 15v2 here enclose an angle with one another, for example an obtuse angle, here an angle of approx. 90 degrees. The plane mirrors 15v1, 15v2 converge in the direction of an edge or—as shown—can collide at an edge. The light deflection device 15v with the two optical surfaces 15v1, 15v2 can be designed here as a single component, alternatively a separate light deflection device can also be provided for each of the optical surfaces. The corresponding explanations for the light deflection device 5v according to FIG. 2 is referred to .

The optical axes of the light sources 14a, i.e. in which this light emits, and/or the optical axis of the detection means 16, i.e. the direction in which light falls into the detection means, are each here, optionally independently of one another, aligned parallel to the longitudinal axis 12a of the workpiece . At least one or both of the optical axes of the light source 14a and the optical detection means 16 can also be aligned in a different direction, if necessary.

It is understood that also according to the embodiment of FIG. 3, a beam splitter can be provided so that the light emitted by a light source is divided into partial beams at least or precisely two preferably adjacent rows of workpieces R can be aligned to produce shadow images of workpieces in these rows. For example, the light deflection mirror 15u can be arranged in the beam path of the light source 14a, so that it deflects only half the light beam from the source 14a in the direction of a row of workpieces and is next to it at an angle of z. B. Another light deflection mirror is arranged at 90°, which deflects the other part of the emitted light beam in the direction of another row of workpieces R.

Fig. 4 shows a further embodiment of an inspection system 21 according to the invention. The differences from the exemplary embodiments in FIGS. 2 and 3 are described below; otherwise, reference is made to the full content of the explanations relating to these figures. The same components as in the previous exemplary embodiments are each increased by "10".

The optical system 25 of the inspection system 21 has a plurality of mirrors 25b here, which are arranged distributed around the circumference of the workpiece 22, the mirror 25b being particularly advantageously arranged here in an arc, more precisely along a circular arc section, around the workpiece 22. Each of the mirrors 25b generates a shadow image of the workpiece, in each case from a different direction, depending on the mirror arrangement. Corresponding to the different directions, a shadow image of a different peripheral area of the workpiece is thus generated by each mirror 25b. The plane of the circular arc section is arranged here at least essentially perpendicularly or perpendicularly to the longitudinal axis 22a of the workpiece. The optical system 25 is arranged here in such a way as to generate shadow images of a longitudinal section, here the free end of the workpiece, for example a pipette tip opening. The (circular) arcuate section on which the plurality of mirrors 25 b is arranged in a distributed manner is formed here essentially as a semicircle. The mirrors 25b are each designed as plane mirrors.

The light emitted by the light source 24a is considered by a Plane mirror trained light deflection device 25a directed towards the plurality of mirrors 25b. The emission surface of the light source 4a and/or the light deflection device 25a, both here, each have a surface in order to irradiate all of the mirrors 25b with a light bundle of parallel light beams. Each individual mirror 25b generates a shadow image of the workpiece 22 , each from a different direction. A plurality of mirrors 25c are arranged behind the workpiece 22 in the direction of the beam path, each of which is also designed as a plane mirror. Each of the mirrors 25b generating a shadow image is provided with a corresponding mirror 25c for projection, here reflection, of the respective shadow image in the direction of the detection means. The mirrors 25c are each arranged here in the straight line connecting mirror 25b-workpiece-mirror 25c. As a result, a plurality of shadow images of the workpiece are generated from different directions, with the shadow images being separated from one another and each being separately detected by the detection means 26 , ie resolved from one another. The capturing means 26 captures the various shadow images simultaneously, possibly also with a time offset. The light emitted by the mirrors 25c in the direction of the detection means 26 can be radiated laterally past the light deflection device 25a onto the detection means 26, if necessary also through the deflection device 25a, which for this purpose can then be used, for example, as a semi-transparent mirror which both reflects as well as having translucent properties.

The optical axis of the light source 24a is arranged here at an angle, more precisely perpendicular, to the longitudinal axis 22a of the workpiece, which forms a structurally compact embodiment that is particularly adapted to special structural situations. If necessary, however, the optical axis of the light source 24a can also be aligned in a different direction to the longitudinal axis 22a of the workpiece by means of suitable light deflection devices. The optical axis of the detection means 26 is here parallel to the longitudinal axis 22a of the workpiece arranged, by means of light deflection devices arranged in the beam path, however, a different alignment of this optical axis can also be given here if necessary.

According to Fig. 4 a separate light source 24a and a separate detection means 26 are assigned to each row of workpieces. This enables the workpiece area to be examined to be irradiated with high light intensity and enables particularly high precision when checking the workpiece. If necessary, however, the light emitted by the light source 24a can also be fed to a beam path splitter in this exemplary embodiment, as shown in FIG. 2 shown in principle, so that different workpieces or Workpieces from different rows can be checked.

Fig. 5 shows the structure of the inspection system 21 according to the embodiment according to FIG. 4 with a plurality of optical detection means 26 which are each associated with 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 rows of workpieces are offset from one another in the direction of movement of the holding device 23 (direction of arrow), which enables a structurally compact embodiment and an adaptation of the system to closely adjacent rows of workpieces. This refinement can also be implemented in all other exemplary embodiments or generally within the scope of the invention. The holding device 23 can, for example, according to FIG. 1 be trained. The majority or Entirety of mirrors 25b arranged in an arc at the respective workpiece inspection position are each in a block or common housing 25bg arranged. 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 greatly simplifies the assembly of the mirrors and the mirrors 25b or 25 c can be adjusted to each other in the housing. The housings 25bg and 25 cg are laterally separated from each other. which is spaced in order to leave a track free on which the respective row of workpieces can be carried out by the optical system by means of the holding device 23 .

Fig. 6 shows an illustration of the optical detection means 26 of the inspection system 21 according to FIG. 4 captured silhouettes . The individual, here five, shadow images B , each corresponding to the number of mirrors of the arrangements of the mirrors 21b and 21b arranged on the light source side and on the detection means side. 25 c, are spatially separated from one another, so that the respective shadow images are separated from one another and can be evaluated separately from one another. The separate evaluation includes that the individual evaluations of the silhouettes can be set in relation to one another, for example to be able to check the concentricity of the workpiece. It goes without saying that the bright image areas of the various shadow images of one workpiece can also overlap one another, as long as the various workpiece shadows, in particular of the free end of the workpiece, are sufficiently resolved separately from one another. In this case, the representation of one of the shadow images B corresponds in principle to a shadow image such as is generated by the other exemplary embodiments of the inspection system or generally within the scope of the invention, taking into account the different workpiece sections checked and, if applicable. other special features of the respective inspection system.

Fig. 7 shows a further exemplary embodiment of an inspection system 31 according to the invention, the differences from the inspection systems described above being described below and, moreover, full reference being made to these exemplary embodiments. Identical components are provided with reference numbers increased by "10".

The light emitted by the light source 34a is in this case radiated onto a light deflection device 35a, with a further connection between the light source 34a and the light deflection device 35a being tere light deflection devices, possibly also a beam path splitter, can be arranged. The light deflection device 35a is in the form of a plane mirror. The light deflection device 35a is designed here as a semi-transparent mirror, which thus has both reflective and transparent properties. The optical system of the inspection device has at least one semitransparent mirror, here the mirror 35a. The light emitted by the light source 34a is thus guided via the semi-transparent light deflection device 35a in the direction of the workpiece 32 to be examined, specifically here, for example, by means of the additional light deflection device 35b in the plane that is at least essentially perpendicular to the longitudinal axis of the workpiece in the direction of the workpiece, as well as then, for example, by means of a beam path splitter 35s onto different workpieces 22 of different workpiece rows RI, R2. The beam path splitter 35s with two optical surfaces 35s1, 35s2 designed as plane mirrors can, like the optical element 15v according to FIG. 3 be constructed. It goes without saying that the angle between the two surfaces of the beam path splitter or optical element 15v generally depends on the particular arrangement of the beam path, so that this angle—generally within the scope of the invention—can be adapted to the particular situation. The optical axis of the light source 34a is in this case arranged in the longitudinal direction of the rows of workpieces R, but with a suitable arrangement of light deflection devices, this can also be aligned differently, if necessary. It goes without saying that a modified version of the inspection system can also be implemented without a beam path splitter, for example, it being possible for a separate light source 34a to be assigned to each row of workpieces. 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 each reflect the light beam incident on them as completely as possible or completely in the direction of emergence of the respective mirror, which can apply to all mirrors of the optical system, except for the partially transparent plane mirror provided or provided in a preferred embodiment. Fig. 7a shows the beam path between light source 34a and detection means 36 only incompletely; this is shown in FIG. 7b complete schematic. The light radiated by the optical surfaces 35s 1 , 35 s2 onto the respective workpiece 32 , which represents the respective shadow image of the workpiece of the row RI or R2 generated is reflected by the plane mirrors 35c1, 35c2 onto the light deflection device 35b, and from this in the direction of or to the semi-transparent light deflection device 35a, and then to the detection means 36, which detects separate shadow images of the workpieces 32 of different rows. The beam path of the detection means 36 is in this case arranged parallel to the longitudinal axis 32a of the workpiece, which, however, is not absolutely necessary with the interposition of further light deflection devices.

This arrangement of a semi-transparent light deflection means 25a can also be implemented in connection with all other exemplary embodiments or generally within the scope of the invention.

Fig. In FIGS. 8a, 8b, FIG. 8 shows sections of two different configurations of optical elements 45 of an inspection system 41 according to the invention. These two configurations can also be implemented generally within the scope of the invention or in relation to the exemplary embodiments, so that the beam path can be adapted to the respective requirements.

Fig. 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 from two light sources 84a projects or redirects .

The arrows in Fig. 8 show the direction of movement of the workpieces 82 as the fixture moves through the optical system. The light deflection device 85v has two optical surfaces 85vl, 85v2, here in the form of plane mirrors, which point in a Angle , here at an angle of approx . 35 to 55° to each other. In relation to the direction of movement of the workpieces (arrow), the light sources 84a are arranged behind the device 85v with respect to the connecting line "detection means 86 - light deflection device 85v". The rays of the beam path enclose an obtuse angle. 2 referenced.

According to Fig. 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 the same, and the shadow image is directed onto the detection means 96 via the light deflection device 95v. The light deflection device 95v here has two optical surfaces 95v1, 95v2, which are at an obtuse angle, here approx. 115°, are employed. In relation 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 means 96 - light deflection device 95v". The rays of the beam path enclose an acute angle. If necessary, in the exemplary embodiments of Figures 8a, 8b or In general, within the scope of the invention, the angle between the two optical surfaces can also be approximately 90°.

Starting from Fig. 8 it goes without saying that a 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, 8b can also be used for other light deflection directions, e.g. for beam path splitters, e.g. B. the beam path splitter 5 s according to FIG. 2 apply. Furthermore, further light deflection devices can be provided corresponding to the arrangement of the light source and the detection means in relation to the rows of workpieces.

Claims

Inspection sy s tem

Claims Inspection system for checking elongated workpieces, especially injection molded parts such as. Pipette tips which have a workpiece longitudinal axis, comprising: a holding device for holding at least one or a large number of workpieces to be checked, which are preferably arranged on the holder in several rows separated from one another by a distance d, an illumination device comprising at least one light source, at least one optical Detection means, wherein the workpiece is arranged in the beam path of the light emitted by the light source between the light source and the optical detection means, and wherein the optical detection means captures the image of the workpiece generated by the illumination device, preferably an optical system for aligning the light emitted by the light source laterally to the workpiece to be checked, which is arranged on the holder, and from the workpiece to the optical detection means, preferably an evaluation device, which transmits signals to the optical detection means smittel is connected and enables an evaluation of the workpiece image, characterized in that the optical system is designed to generate a shadow image of the workpiece from at least one direction transverse to the longitudinal axis of the workpiece and to project the generated shadow image onto the detection means. Inspection system according to Claim 1, characterized in that the optical system comprises at least one plane mirror which directs the light from the light source onto the workpiece. Inspection system according to Claim 2, characterized in that the plane mirror is arranged directly in front of the workpiece in the beam path between the light source and the workpiece. Inspection system according to one of Claims 1 to 3, characterized in that the optical system has at least two plane mirrors arranged one behind the other in the beam path in the beam path between the light source and the workpiece. Inspection system according to one of Claims 1 to 4, characterized in that the optical system is designed in such a way that the rays incident on the workpiece, which produce the shadow image of the workpiece, are a light bundle of rays aligned at least essentially parallel to one another. Inspection system according to one of Claims 1 to 5, characterized in that the optical system in the beam path between the light source and the workpiece consists exclusively of plane mirrors and/or that the optical system in the beam path between the workpiece and the optical detection means consists exclusively of plane mirrors. Inspection system according to one of Claims 1 to 6, characterized in that the beam path has at least one beam path splitter, which splits the light emitted by a light source into at least two separate partial beams and divides the at least two partial beams into one and 60 straightens the same workpiece to produce at least two shadow images of the same. Inspection system according to one of Claims 1 to 7, characterized in that at least two or all of the partial beam paths are designed in accordance with one of Claims 2 to 6. Inspection system according to one of Claims 1 to 8, characterized in that a light deflection device of the optical system is provided in the beam path between the light source and the workpiece in the light which is radiated onto the workpiece at least essentially perpendicularly to the longitudinal axis of the workpiece, and

(i) that with respect to the irradiation direction of the light in the plane that is at least essentially perpendicular to the longitudinal axis of the workpiece and/or

(ii) that in the direction of movement of the holding device through 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, and that the two parts of the light deflection device each produce a shadow image of one workpiece. Inspection system according to Claim 9, characterized in that that part of the light deflection device which is arranged in front of and/or behind the workpiece in relation to the direction of incidence in the plane in front of and/or behind the workpiece each comprises at least one plane mirror and/or that the parts of the light deflection device are each designed as plane mirrors . Inspection system according to Claim 10, characterized in that the part of the light deflection device arranged in front of and/or behind the workpiece is directly in front of or behind the 61

Workpiece is arranged to create a shadow image of the workpiece.

12 . Inspection system according to one of Claims 9 to 11, characterized in that the light deflection devices which are arranged in the plane in front of and behind the workpiece in relation to the direction of incidence and which each produce a shadow image of the workpiece are at an angle of h 20 in relation to the workpiece ° and/or 170°, preferably approx. 90° to each other.

13 . Inspection system according to one of Claims 1 to 12, characterized in that the optical system in the beam path upstream of the workpiece comprises a plurality of mirrors, each preferably as a plane mirror, which are distributed around the circumference of the workpiece and which each form a shadow image of the workpiece.

14 . Inspection system according to one of Claims 1 to 13, characterized in that the optical system in the beam path downstream of the workpiece comprises a plurality of mirrors, which are distributed around the circumference of the workpiece, and in that at least one or all of the mirrors downstream of the workpiece have a are assigned to the plurality of mirrors that produce a shadow image and that the mirrors downstream of the workpiece deflect the shadow image produced by the respective mirror in the direction of the detection means.

15 . Inspection system according to one of Claims 1 to 14, characterized in that the mirrors producing a shadow image and the mirrors downstream of the workpiece in the beam path each surround part of the circumference of the workpiece.

16 . Inspection system according to one of claims 1 to 15, characterized in that on the lighting side to the workpiece 62

plane mirror is provided, which aligns the light emitted by the lighting device directly onto several or all of the mirrors arranged distributed around the circumference of a workpiece, and/or that a plane mirror is provided on the detection means side for the workpiece, which of several or all of the mirrors arranged around the circumference of a workpiece Distributed mirrors project shadow images of the workpiece to the detection means.

17 . Inspection system optionally according to the preamble of Claim 1 or according to one of Claims 1 to 16, characterized in that the holding device has at least two rows of holders spaced apart from one another, each for at least one or exactly one workpiece, and that a light deflection device is provided between the workpiece and the detection means which aligns the shadow images of two workpieces from different rows onto the detection means.

18 . Inspection system according to Claim 17, characterized in that the detection means is designed to simultaneously detect the shadow images of workpieces in different rows.

19 . Inspection system according to the preamble of Claim 1 or according to one of Claims 1 to 18, characterized in that the holding device has at least two rows of holders spaced apart from one another, each for at least one or exactly one workpiece, and that a beam path splitter is provided between the light source and the workpiece is , which divides the beam path of the light source and preferably aligns it to different rows at the same time .

20 . Inspection system according to one of claims 17 to 19, characterized in that the detection means and / or a light deflection device, which light from the light source to and aligns different rows, and / or that a light deflection device, which deflects light from the workpiece to the detection means, is arranged between the rows.

21 . Inspection system according to one of Claims 1 to 20, characterized in that the light source of the illumination device is at least essentially a point source.

22 . Inspection system according to one of Claims 1 to 21, characterized in that the optical axis of the light source of the lighting device and/or of the detection means is aligned parallel to the longitudinal axis of the workpiece.

23 . Inspection system according to one of Claims 1 to 22, characterized in that the optical system has an optical element which is designed to be partially transparent and which is visible both in the beam path of the light or Arranged in the beam path and at the same time in the light falling from the workpiece in the direction of the detection means.

24 . Inspection system according to one of Claims 1 to 23, characterized in that the optical system is designed to irradiate the workpiece to be examined with at least two separate partial beams of at least one light source in order to produce a different shadow image of the respective workpiece with each partial beam that the separate partial beams between the workpiece in its examination position and the detection means have a different beam path length, and that an optical element is arranged in at least one of the beam paths of the partial beams between the workpiece and the detection means in order to align the image sharpness of the different shadow images in the detection means with one another. Inspection system according to one of Claims 1 to 24, characterized in that the optical system is designed to generate an undistorted shadow image of the workpiece from at least one direction transverse to the longitudinal axis of the workpiece and/or to project the generated shadow image undistorted onto the detection means. Inspection method for checking elongated workpieces using the inspection system according to any one of claims 1 to 25. Inspection method according to Claim 26, characterized in that the holding device for holding at least one or a large number of workpieces to be checked is moved relative to the optical system in order to move the respective workpiece to be checked from a non-examination position into an examination position on which the shadow image of the workpiece is generated optical system to convert, and that the exposure time of the workpiece to generate its at least one silhouette is less than / equal to 1 millisecond.