Apparatus for inspecting two opposite edge sides of a transported planar object and use of the apparatus therefor

Abstract

Apparatus for inspecting two opposite edge sides of a transported planar object and use of the apparatus therefor An apparatus for inspecting two opposite, right and left edge sides (93, 94) of a transported planar object (90) with respect to a transport direction (101) is described, wherein surfaces of the left and right edge sides (93, 94) are oriented parallel to the transport direction (101). The apparatus (1) comprises a transport device (2) for moving the object (90) transported in the transport direction (101) with a support plate (21) and with a transport surface (31). For inspecting the right and left edge sides (93, 94) of the object (90), the apparatus (1) respectively comprises of an inspection device (5) with an imaging unit (50) comprising microscope optics (51) and with an illumination unit (52) comprising bright field illumination (53) and / or dark field illumination (54). The support plate (21) of the transport device (2) has at each imaging area (56) of the right and left inspection devices (5, 62, 63) a first recess (26) in the edge (22, 23) of the support plate (21). A use of the apparatus for inspection is also described.

Description

[0001] Apparatus for inspecting two opposite edge sides of a transported planar object and use of the apparatus therefor

[0002] The invention relates to an apparatus for inspecting two opposite right and left edge sides of a transported planar object with respect to a transport direction, wherein the right and left edge sides of the object connect an upper side and a lower side of the object and wherein the surfaces of the left and right edge sides are oriented parallel to the transport direction, and to a use of the apparatus for this purpose.

[0003] The planar objects may in particular be thin objects compared to their surface extensions (along the upper and lower sides). Thin objects in this sense may in particular be objects in which at least one surface direction is at least about 50 or 500 times larger than their height (oriented perpendicular to the surface). The edge sides extend along a length and a width of the object. For the apparatus according to the invention, the width of the object is in any case defined as a direction progressing transversely to the transport direction.

[0004] In a particularly preferred embodiment, the objects are transparent or partially transparent objects, such as thin glass panes or plastic films, wafers or the like. Glass panes or plastic films for displays, in particular for foldable displays of, for example, smartphones, or other applications in which material defects in the edge sides of the objects have a lasting effect on the quality of the objects and should therefore be identified immediately after production.

[0005] It has been shown that foldable displays that later show defects in the crease area (such as tearing or breaking) during use often comprise micro-scratches or micro-cracks on the edge side in the area of the later defect after manufacture. The apparatus proposed according to the invention comprises a transport device for moving the object transported in the transport direction. In a transport plane of the transport device, the transport device comprises a support plate aligned parallel to the lower side of the object, wherein the width of the support plate between a right edge and a left edge of the support plate relative to the transport direction corresponds (essentially) to a width of the object between the right and left edge sides. The support plate can form a (preferably planar) surface corresponding to the (preferably planar) lower side of the object, so that the object can be arranged with the lower side opposite the support plate on the transport device in the transport plane. According to the invention, the support plate thus also forms or is a support surface for the object. The transport plane is not to be understood as a surface in the mathematical sense, which comprises no height extension. In any case, in a direction perpendicular to the support plate, the transport plane has the height of the object, a gap between the object and the support plate and preferably at least part of the height of the support plate. The transport device also comprises at least one transport surface which engages the object and moves the object in the transport direction.

[0006] Furthermore, the apparatus for inspecting the right and left edge sides of the object comprises for each side an inspection device, i.e. a right inspection device on the right edge of the support plate and a left inspection device on the left edge of the support plate.

[0007] Each inspection device comprises an imaging unit (camera) with microscope optics and an illumination unit having a bright field illumination (in particular a reflective bright field illumination RBF - Reflection Bright Field) and / or a dark field illumination (in particular a reflective dark field illumination RDF - Reflection Dark Field). With bright field illumination, light is reflected from a smooth surface directly into the imaging device. The surface appears bright and well illuminated in the image. With dark field illumination, light from a smooth surface is not reflected directly into the imaging device. The surface appears dark in the image. Bright pixels result from surface structures (such as scratches, elevations) and allow the surface structures to be easily recognized.

[0008] According to the invention, (at least) one right-hand inspection device is arranged in front of the right-hand edge of the support plate such that the righthand edge side of the object transported by the transport surface is moved through the imaging area of the microscope optics (and thus also of the imaging unit) of the right-hand inspection device, and (at least) one left inspection device is arranged in front of the left edge of the support plate such that the left edge side of the object transported by the transport surface is moved through the imaging area of the microscope optics (and thus also of the imaging unit) of the left inspection device. This allows the right and left edge sides of the transported object to be completely imaged during transport.

[0009] The width of the support plate essentially corresponds to the width of the object. This means that the inspection devices arranged on the right and left edges of the support plate comprise a focus range of the microscope optics that lies within the imaging area of the imaging device. There is a certain amount of tolerance here within the depth of field. In other words, the inspection devices are arranged in the transport plane in front of the right and left edges of the support plate and in front of the left and right side edges of the transported object respectively, so that their imaging area gathers the edge sides of the object and areas above and below the object.

[0010] Optical inspection devices for edge detection are already known. US 2019 / 0047895 A1 describes a cutting and inspection device for glass strips, wherein light is fed into a first recess of the glass strip in a bright field or dark field arrangement and guided through the glass strip. An image is taken of the second front side opposite the first front side of the glass strip and evaluated in high resolution to assess the surface quality of the front side using various image evaluation methods. The method allows the surface quality of the front sides to be evaluated during transport on a non-contact transport device. However, simultaneous evaluation of opposite front sides (edges) of the glass strips is not possible or costly because imaging is only carried out on one side of the glass strips.

[0011] DE 10 2023 103 520 B3 describes an apparatus and a method for optically inspecting the surface, in particular of thin glass panes, plastic films, wafers or similar objects during transport. To avoid mechanical damage to these fragile objects, a sonotrode transport device with a levitation or support surface is proposed as transport device, which generates vibrations (in particular ultrasonic vibrations) that cause the object to hover above the support surface without contact. The support surface is inclined perpendicular to the transport direction, so that one edge side of the object rests against a transport surface (e.g. in the form of a conveyor belt) and is moved in the transport direction. The upper side of the object can be inspected by means of an inspection device in a reflection arrangement or transmission arrangement, wherein the imaging device is arranged above the upper side of the object. In a transmission arrangement, an illumination unit of the inspection device is located below the support surface at a slit through which light can be shone through the support surface onto the lower side of the object. It is not possible to inspect the edges (edge sides) of the object in such an arrangement because one of the edge sides is in contact with the transport surface and is covered by it. In addition, it is not possible to arrange the inspection device approximately vertically in front of the surface of the edge sides. However, this is necessary for an accurate inspection of the edge sides. The problem of the invention is therefore to propose a simple way of accurately optically inspecting the edge sides of a moving object.

[0012] According to the invention, this problem is solved by an apparatus having the features of claim 1 . According to the invention, in an apparatus of the type described at the beginning, it is provided that the support plate of the transport device comprises at the imaging area of in particular eich ot the right and left inspection devices a first recess in the edge of the support plate facing the respective inspection device, wherein each first recess is shaped such that the width of the support plate between its right edge and its left edge is reduced in the region of the recess. In other words, each recess in the edge of the support plate is directed towards the opposite edge of the support plate. This has the effect, that an area of the lower side of the object is not covered by the support plate in the area of the recess during transport in the transport device. The object therefore lies freely above the support plate in the area of the recess. This avoids unwanted reflections of light emitted by the illumination unit from the support plate into the imaging unit, which can lead to unwanted artifacts in the images of the imaging unit and to incorrect evaluations when detecting defects on the edge sides (edges) of the object.

[0013] In addition, the edge of the support plate (set back from the edge side of the object) in the area of the first recess is no longer in the depth of field of the imaging area and is displayed out of focus, even if at least part of the support plate is in the imaging area. This also facilitates image evaluation.

[0014] According to a preferred embodiment of the invention, the imaging unit and the illumination unit of the (e.g. each right and left) inspection device can be arranged in a reflection arrangement. This means that the illumination unit and the imaging unit of the inspection device are arranged on the same side with respect to the edge side (edge) of the object and light reflected at the edge side is reflected into the imaging unit. This allows both reflective bright field illumination and reflective dark field illumination to be realized, with which a large number of surface defects in the edge sides (edges) of the object can be easily detected. Bright field illumination and dark field illumination are two different optical channels for detecting and identifying different defects in the edge side of the object.

[0015] In this context, it is particularly advantageous if a (lateral, not opposite the lower side of the transported object) surface of the support plate (at least) in the area of the recess is designed as a matted surface and / or forms an obtuse angle to a plane oriented parallel to the lower side of the transported object. A matted surface can be achieved by a roughened surface (e.g. with a grainy texture) and / or by a (e.g. dark) color, so that light incident on the surface is largely absorbed and / or reflected in a color in which the imaging device is not sensitive, e.g. by a filter. An obtuse angle can be selected by the skilled person such that light from the illumination device reflected from the surface of the support plate in the area of the recess is not reflected into the imaging device and / or in the direction of the transported object (i.e. in particular not or as little as possible through the recessed area of the support plate). This represents a particularly preferred embodiment of the invention with regard to avoiding interfering light effects.

[0016] According to a further embodiment of the invention, an inspection device according to the invention can be designed as a structural unit in which the imaging unit and the illumination unit are fixed relative to each other. This ensures optimum illumination in the imaging area of the inspection device because the orienting of the illumination unit and the imaging unit relative to each other does not change. In addition, according to a further embodiment of the invention, the inspection unit can be surrounded by a mostly closed housing, which protects the optical components and shields the imaging unit well against diffuse stray light. Only a small opening in the optically active area of the imaging unit and the illumination unit, which mostly coincides and requires a comparatively small opening directly in front of the object, is required.

[0017] A particularly preferred embodiment of the invention provides for the right and left inspection devices to be arranged opposite one another on the right and left edges of the support plate at the same position with respect to the transport direction. These inspection devices arranged opposite one another have the advantage that the inspection device is particularly compact in the transport direction and can be easily integrated into production and conveyor lines.

[0018] A further advantage of this arrangement is that the apparatus according to a preferred embodiment can be operated according to the invention such that light from one of the right or left inspection devices arranged opposite one another is coupled into one of the right or left edge sides of a transparent object and (corresponding to a light guide) is guided through the transparent object, so that the transmitted light illuminates the other right or left edge side from the inside. The edge side illuminated from the inside is imaged by the other of the right or left inspection devices arranged opposite each other. This opens up a further optical channel (preferably in addition to the reflective bright field illumination and the reflective dark field illumination), which further improves the detection and identification of defects in the edge side of the object. This additional optical channel is called the edge-light channel (or transmission illumination).

[0019] According to the invention, the apparatus may comprise a control system for controlling the imaging units and the illumination units of the inspection directions. Such a control system can be integrated into a suitable control device of the apparatus. Particularly in the case of inspection devices arranged opposite each other, but also in the case of inspection devices arranged differently, the control system can be adapted for a clocked and / or synchronized control of the imaging units and illumination units of the inspection devices. This is particularly advantageous for inspection devices arranged opposite each other to control all (e.g. three) optical channels on each of the two sides during the transport of the object without influencing each other such that seamless monitoring of both edge sides of the object is possible in real time. This also applies to fewer optical channels. Due to the good illumination with the illumination units, short exposure times are realized, so that with respect to the transport speed of the object, each edge side can be completely imaged even with correspondingly clocked imaging with different illumination (bright field, dark field, edge light), because each image captures a certain edge section. The skilled person can adapt the timing and exposure time of the various imaging processes to the transport speed.

[0020] Furthermore, the control can be synchronized with the transport speed, in the sense that each imaging is assigned a transport position of the object to easily localize the defects detected on an object.

[0021] A particularly compact and advantageous embodiment of the invention can be achieved by designing a bright field illumination of the illumination unit as confocal illumination with the microscope optics.

[0022] Additionally or alternatively, a dark field illumination can be arranged above and / or below a transport plane of the transport device. In the transport plane, the object is transported in the transport direction. In this embodiment, the dark field illumination is directed towards the imaging area of the imaging unit. A dark field illumination arranged above and / or below the transport plane can preferably be used for the edge light channel. The light coupled in on one edge side from above and / or below the transport plane is reflected from the inside on the upper side and the lower side of the transparent object and coupled out again on the opposite edge side. The decoupling angle on the opposite edge side is the same angle as during coupling. This results in a dark image being generated in the edge light channel in the defect-free case, because the decoupled light is not coupled into the imaging unit of the opposite inspection device in the defect-free case. Defects at the edge scatter the light into the camera and light up brightly. The use of dark field illumination therefore creates an edge channel dark field for the edge light channel. This is a particularly preferred edge light channel.

[0023] In principle, bright field illumination, in particular illumination confocal with the microscope optics, can also be used as an edge light channel. The light coupled in at one edge side illuminates the transparent object and is coupled out at the opposite edge side and imaged by the imaging unit of the opposite inspection device.

[0024] According to a further aspect of the invention, the support plate may comprise at least one spacer element which holds the lower side of the transported object at a gap distance from the surface of the support plate. In the event of a relative movement of the transported (i.e. moving) object with respect to the support plate, this has the advantage that the lower side of the transported object at least does not rest flat on the support plate. This reduces friction and therefore possible damage to the surface of the transported object.

[0025] According to a simple embodiment, the spacer elements can be rotary elements mounted on the support plate, e.g. rollers mounted around an axis or guided balls, which allow an axis of rotation parallel to the plane of rotation and perpendicular to the direction of transport. This results in very little friction on the lower side of the transported objects. In addition, the rollers or balls can be made of an elastic, in particular rubberized, material or comprise a corresponding coating to further reduce the risk of damage to the object.

[0026] In a further development of this embodiment, a plurality of spacer elements may be provided, and at least one of the spacer elements may form a (or the at least one) driven transport surface. Such a spacer element may preferably be a roller rotatable about a driven axis of rotation, the surface of which engages (directly or indirectly) the lower side of the object and transports the object in the transport direction. Preferably, several such driven rollers can be provided at a distance from each other. When the rollers themselves come into contact with the lower side of the object, they engage directly with the lower side of the object. According to the invention, an indirect drive can be achieved by tensioning a conveyor belt over each of at least two rollers (or by tensioning several conveyor belts consecutively in the transport direction). In this case, the driven rollers with the conveyor belt(s) form the transport surface of the transport device. The advantage of such an arrangement is that the object is stationary on the conveyor belt and does not move relative to it. This further reduces the risk of damage to the object.

[0027] According to the invention, no spacer elements can be provided in the area of the recess.

[0028] There are particularly fragile objects whose surface is particularly susceptible to damage. Examples of such objects, which are usually in the form of plates or webs, can be, for example, thin or ultra-thin glass panes or films with a height / thickness in the range between approximately 0.03 to 1 mm, such as those used for displays, but also as carrier layers for microchips, such as wafers made of semiconductor material or the like. Surfaces of such materials should preferably not be physically contacted during transport. For such applications, according to a preferred embodiment, the support plate may comprise a levitation surface as a spacer element, which holds the object above the support plate without physical contact in the gap distance. This reliably prevents mechanical damage to the surface of the object during transport.

[0029] One possibility for forming the spacer element as a levitation surface can be the formation of a compressed air system on or in the support plate, wherein pressure nozzles are provided in a planar arrangement in the support plate on the surface opposite the lower side of the transported object along the transport path and are connected to the compressed air system. Compressed air escapes from the pressure nozzles during transport. By adjusting the number of nozzles and / or the pressure of the compressed air supplied, the pressure force acting on the object can be adjusted so that the transported object is held at a gap distance above the support plate.

[0030] The compressed air system can be controlled by the control system proposed according to the invention or by a higher-level control system of the transport device. In this text, compressed air is understood to be any compressible, gaseous fluid with which a positive pressure can be generated. Ambient air is a cost-effective and simple example of this and can be used according to a preferred embodiment.

[0031] According to a particularly preferred embodiment, the levitation surface can be designed as a sonotrode. Sonotrodes are based on acoustic levitation, in which ultrasonic waves are applied to a fluid, usually a gas such as ambient air, by vibration exciters. The resulting subsonic wave exerts a pressure or force on the surface (lower side) of the object in the path of the pressure waves. If the ultrasonic wave is oriented against an attractive force, it counteracts the attractive force and can cause the object to float. The principle of sonotrodes is known in the prior art for the contactless transport of lightweight, fragile materials. Reference is made here by way of example to WO 2015 / 010681 A2, WO 2009 / 056127 A2 or DE 10 2023 103 520 B3. The use of such a sonotrode is easily possible, for example also by means of control by the control system provided according to the invention.

[0032] The sonotrode enables the object to be held during transport by the inspection submission in a gap above the support plate, which may extend over the length of the entire transport device, which may be longer than the area in which the inspection devices of the apparatus according to the invention are arranged.

[0033] For additional stabilization of the object, suction openings (preferably evenly distributed over the entire surface) can be provided in the levitation surface, which is designed as a sonotrode, to which a negative pressure is applied. This creates a negative pressure in the gap between the support plate and the lower side of the object, which counteracts the levitation force of the ultrasonic waves and pulls the object towards the support plate. As long as the total attractive force is smaller than the levitation force, the object is kept at a spacing (gap) from the support plate and stabilized at the same time. The total attractive force can be adjusted by controlling the negative pressure. Increasing the stability of the object during transport facilitates optical inspection.

[0034] However, the sonotrode does not yet transport the object in the transport device along the transport direction. For this purpose, DE 10 2023 103 520 B3 proposes a simple solution using gravity, in which the levitation surface is tilted transversely to the transport direction with respect to the horizontal plane (i.e. a plane aligned horizontally with respect to the force of gravity), for example by an angle of about 60° with respect to the horizontal plane or by an angle of 30° with respect to the direction of the force of gravity. This causes the object on the support plate or levitation surface to slide towards the lower (right or left) edge of the support plate. A conveyor belt protrudes at right angles from the support plate as a transport surface. The transport surface holds the object by one of the right or left edge sides of the object resting against the transport surface and being moved in the transport direction by a movement of the transport surface.

[0035] In the state of the art, various illumination and camera devices are provided above and below the upper and lower sides of the object for optical inspection of the surfaces of the object aligned parallel to the levitation surface in a reflection or transmission arrangement. A narrow slit or small gap is formed in the levitation surface and the conveyor belt to allow light to pass through. The width of the gap in the conveyor belt corresponds approximately to the width of the slit so as not to obstruct the optical inspection of the glass pane. In this arrangement, however, it is not possible to inspect the edge side of the object adjacent to the transport surface because an inspection device with microscope optics, bright field illumination and dark field illumination cannot be arranged in front of an edge side of the object.

[0036] In this context, the invention proposes (in particular in connection with a sonotrode, but also independently thereof) that the support plate is tilted transversely to the transport direction relative to a horizontal plane (i.e. a plane oriented horizontally with respect to the earth's gravitational force). Protruding from the support plate in the direction of the transport plane and directed parallel to the direction of transport, the transport surface is designed to abut one of the right or left edge sides of the object, wherein the transport surface comprises a second recess in the region of the first recess of the support plate, at which one of the inspection devices is arranged. In this embodiment, the inspection device is thus arranged according to the invention on a side of the transport surface facing away from the object such that the microscope optics optically gathers the imaging area through the second recess. The same can apply to the bright field illumination, in particular if this is preferably designed as confocal illumination with the microscope optics as according to the invention, and illuminates the imaging area.

[0037] The tilt angle to the horizontal plane is preferably in a range between 20° and 80°, particularly preferably in a range between 25° and 40°, and according to a very preferred embodiment can be about 30° (e.g. with a deviation of + / - 5%, which is regarded as "about 30°" in the context of the disclosure.

[0038] The transport surface is preferably designed to protrude vertically from the support plane. As a result, the edge side of the object lies largely planar against the transport surface, which minimizes the risk of damage to the edge sides of the transported object during transport.

[0039] In a particularly preferred further development of this embodiment, it can be provided according to the invention that the dark field illumination is arranged above and below a transport guide of the transport surface such that the light emitted by the dark field illumination directly illuminates the imaging area through the second recess. With the arrangement above and below the transport guide of the transport surface, the dark field illumination irradiates at an angle onto the edge side of the object, so that reflected light from the dark field illumination does not fall into an inspection device arranged in front of the edge side of the object, whose microscope optics optically gather the imaging area through the second recess. The angle of incidence of the dark field illumination on the imaging area can particularly preferably be around 45°, preferably in an angle range between 40° and 50° and preferably at least in an angle range between 30° and 60°.

[0040] According to a preferred embodiment according to the invention, the right and / or left inspection device (or each of the right and left inspection devices) arranged in the transport plane in front of the right and / or left side of the support plate can be oriented with the optical axis of the inspection device (or the imaging unit of the optical inspection device) such that the optical axis runs perpendicular to the surface of the edge side. According to the invention, this should include that the optical axis of the inspection device progresses essentially perpendicular to the surface of the edge side (i.e. in the direction of the surface normal), particularly preferably at an angle of + / -1 ° relative to the surface normal, preferably at an angle of + / -5°, and preferably at least at an angle of + / - 15°. Usually, the optical axis of the inspection device will lie in the transport plane and run through the imaging area. Usually, the optical axis is also oriented substantially parallel to the surface of the support plate facing the lower side of the object, and thus usually also substantially parallel to the upper side and the lower side of the object.

[0041] This allows the surface of the edge side to be inspected particularly well.

[0042] On the side of the transport plane facing away from the support plate, in which the object is transported, the light of the dark field illumination is preferably radiated into the imaging area through the second recess in the transport plane in accordance with the invention.

[0043] On the side of the transport plane facing the support plate, in which the object is transported, the light of the dark field illumination is preferably emitted through the second recess in the transport surface and into the imaging area through the first recess in the support plate, in accordance with the invention.

[0044] According to the invention, the support plate and the transport guide also have possible support structures above and below an area gathered by the first and second recess, which is kept free both optically and for arranging components of the inspection devices, for example in order to fix the dark field illumination above and below the transport guide and to enable an optically free view of the imaging area. The same applies to other described functions of the apparatus. In particular, it is provided according to the invention that the area above and below the transport guide in front of the first recess of the support plate for arranging the inspection device is also unobstructed.

[0045] According to a further embodiment of the invention, the transport surface can be formed as part of a conveyor belt rotating on guiding pulleys. Thus, the conveyor belt (which is regarded as a conveying surface in the context of the disclosure) rotates correspondingly driven on the guiding pulleys. In this embodiment, the second recess can be formed by the conveyor belt being interrupted in the region of the second recess by comprising, in the transport direction each upstream and downstream of the second recess, a guiding pulley formed as a deflecting pulley of a first conveyor belt upstream of the second recess and of a second conveyor belt downstream of the second recess. Together, the first conveyor belt and the second conveyor belt form a transport surface of the transport device of the apparatus in the area of the inspection devices. The spacing of the deflecting pulleys is such that the microscope optics optically gathers the imaging area through the second recess between the deflecting pulleys with the conveyor belt circulating thereon. Between a plane formed by the axes of the deflecting pulleys and the imaging area, the second recess widens due to the cylindrical shape of the deflecting pulleys. According to the invention, this widening of the second recess serves for the light irradiation of the dark field illumination into the imaging area.

[0046] For the support plate also not interfering with this light irradiation, it is proposed according to a particularly preferred embodiment of the invention that the length of the first recess in the transport direction on the edge of the support plate is larger than the corresponding length of the second recess on the area of the transport surface facing the support plate. According to a preferred embodiment of the invention, the length of the second recess in the transport direction at the area of the transport surface facing the support plate can correspond to approximately or at least three times the length of the imaging area in the transport direction. This enables sufficient irradiation of the dark field illumination.

[0047] Furthermore, in a further or combined embodiment, it may be provided that the length of the second recess in the transport direction at its narrowest point corresponds to approximately or at least twice the length of the imaging area in the transport direction. This enables interference-free imaging with the microscope optics and interference-free bright field illumination, in particular with bright field illumination designed as confocal illumination.

[0048] In another embodiment according to the invention, the transport surface can be designed as a suction surface embedded in the support plate for generating a negative pressure and fixing the transported object, wherein the suction surface is movable relative to the support plate / support surface in transport direction (and is moved in this direction accordingly for transport). In this embodiment, the suction surface acts as a gripper and also enables an overhead arrangement of the invention, in which the support plate is arranged above the transported object. Accordingly, in such an arrangement, the lower side of the transported object facing the support plate also points upwards with respect to the spatial direction. In this embodiment, the apparatus according to the invention is independent of the arrangement and orienting in space. The suction force generated by the suction surface can be suitably adjusted by controlling the negative pressure, which is supplied to the suction opening via a negative pressure system. The negative pressure system is connected to the suction surface for applying the negative pressure. This embodiment is also possible with a support plate designed as a sonotrode, wherein the intensity of the generated ultrasonic waves and the generated negative pressure are adjusted to each of the objects, in particular by a control system provided.

[0049] According to the invention, the apparatus may further comprise a control device adapted to control the inspection devices and / or the transport device. As already described, the control of the inspection devices can include, in particular, clocked control of the imaging units and the illumination units of the right and left inspection units in order to achieve for each inspection device the multiple, for example up to three, optical channels described in the seamless inspection of the edge sides of the transported objects in real time, i.e. at the transport speed provided in the transport device. The inspection devices can be controlled in synchronization with the transport device, so that the position of the object transported in the transport device is known for each image of the inspection device. This enables simple and possibly even automated assignment of defects detected in the images of the inspection devices and their position on the object.

[0050] Furthermore, the control device can be adapted to control the transport device. This can include setting the transport speed by acting on the movement of the transport surfaces, setting oscillation generators of a levitation surface of the support plate designed as a sonotrode and / or setting a negative pressure of a fluid introduced into the support plate for gripping and transporting the object and / or for stabilizing the object and or a positive pressure of a fluid introduced into the support plate for generating a levitation effect.

[0051] According to the invention, it is also possible for the transport device belonging to the invention to be part of a longer transport device in the area of the inspection units, on which one or more further inspection apparatus, such as an inspection apparatus described in DE 10 2023 103 520 B3, and / or manufacturing devices are arranged as part of a process line. In this case, the control system proposed according to the invention can also be integrated into a separate transport control device of the entire transport device. Preferably, suitable interfaces to the control device for controlling the inspection devices can be provided. The design of the transport device according to the invention in the area of the apparatus according to the invention for inspecting the edge sides of objects can be realized by connecting suitable support plates and transport surfaces as described above. Therefore, the apparatus proposed according to the invention can be easily integrated into corresponding transport devices.

[0052] The invention also relates to the use of an apparatus as described above, in particular according to one of claims 1 to 14, for inspecting two opposite edge sides, right and left with respect to a transport direction, of a transported planar object. In the context of this use according to the invention, in particular a method for inspecting two opposite edge sides, right and left with respect to a transport direction, of a transported planar object can be carried out by means of an apparatus according to claim 14, in which the control device is adapted to control the transport device for transporting the object in the transport direction and to control the imaging unit and the illumination unit for imaging in at least one of the following optical channels: (a) reflective bright field illumination, (b) reflective dark field illumination, (3) transmission illumination, i.e. edge-light illumination. The optical channel of the edge-light illumination (transmission illumination) can have several sub-channels as described, in particular a lightedge dark field illumination and / or a light-edge bright field illumination.

[0053] According to the invention, imaging of the right and left edge sides of the object can be imaged in all optical channels. The optical channels have already been described. Reference is made to this. According to the invention, in the use or the method described above, it can be provided in the context of the use of the apparatus that the images taken are fed to an image evaluation for the detection and / or identification of defect locations. Such image evaluation can be realized by the skilled person within the framework of image evaluation methods known in the art.

[0054] Further advantages, features and potential applications of the invention are also apparent from the following description of embodiments and the drawing. All the features described and / or illustrated together or in any combination that makes sense to a skilled person belong to the object of the invention, even independently of their combination in the described or illustrated embodiments or in the claims.

[0055] It shows:

[0056] Fig. 1 a three-dimensional view of an embodiment of an apparatus according to the invention, which is integrated into a conveyor line.

[0057] Fig. 2 an enlarged sectional excerpt of Fig. 1 with the object transported in the apparatus according to the invention;

[0058] Fig. 3 a top view of the apparatus according to the invention shown in Figs. 1 and 2 essentially from above; and

[0059] Fig. 4 a schematic side view of the embodiment shown in Figs. 1 to 3.

[0060] Fig. 1 shows an apparatus 1 according to the invention for inspecting two opposite, right and left edge sides of a transported planar object 90 (not shown in Fig. 1 ) with respect to a transport direction 101 represented by an arrow. The apparatus 1 according to the invention is integrated into a conveyor line 100, in which the object 90 is transported through several stations, for example in a production and / or quality control. The apparatus 1 according to the invention can be one of these stations in the conveyor line 100. Here, an inspection apparatus 110 for optically inspecting the transported object 90 is shown in front of the apparatus 1 in the transport direction 101 of the conveyor line 100, as described by way of example in DE 10 2023 103 520 B3. Such a combination is useful according to the invention, because the inspection apparatus 110 described in DE 10 2023 103 520 B3 performs an inspection of the large-area upper side 91 and lower side 92 of the transported object 90 by means of optical inspection. The inspection device 150 of the inspection apparatus 110 is only partially shown and will not be described in more detail here.

[0061] The apparatus 1 according to the invention comprises a transport device 2 for moving the object 90 transported in the transport direction 101. The transport device 2 comprises, in a transport plane 20 of the transport device 2, a support plate 21 aligned parallel to the lower side 92 of the object 90, which holds the object 90 in the transport plane 20. The width 24 of the support plate 21 , shown by a double arrow, between a right edge 22 and left edge 23 of the support plate 21 with respect to the transport direction corresponds (essentially) to a width 95 of the object 90 between the right edge side 93 and left edge side 94 of the object 90. This is shown in Fig. 2, which shows a enlarged sectional excerpt of Fig. 1 with the object 90.

[0062] The support plate 21 forms a surface corresponding to the (preferably planar) lower side 92 of the object 90, which corresponds to the transport plane 20 in the drawing. The object 90 can be arranged with its lower side 92 opposite the support plate 21 on the transport device 2 in the transport plane 20. The transport device 2 further comprises a transport surface 31 , which engages the object 90 and transports the object 90 in the transport direction 101. For this purpose, the transport surface 31 moves relative to the support plate 21 itself in the transport direction 101.

[0063] In the embodiment shown in Fig. 1 to Fig. 4, the transport surface 31 is part of a conveyor belt 32 rotating on guiding pulleys I deflecting pulleys. Only the axles 33 of the guiding pulleys I deflecting pulleys are visible in the figures. The guiding pulleys I deflecting pulleys themselves are covered by cover plates not designated by reference signs. The conveyor belt 32 (with the transport surfaces 31 ) and the guiding pulleys I deflecting pulleys are part of a transport guide 34, which arranges the transport surface 31 in front of the (in the example shown) left edge 23 of the support plate 21 . Accordingly, the left edge side 94 of the transported object 90 is also in contact with the transport surface 31 , so that the object 90 is moved with the transport surface 31 in the direction of movement 101.

[0064] As shown in particular in Fig. 1 , the support plate 21 is tilted by an angle a transverse to the transport direction 101 with respect to a horizontal plane 102 (i.e. a plane aligned horizontally with respect to the force of gravity). The transport surface 31 correspondingly is designed to protrude from the support plate 21 in the direction of the transport plane 20 and parallel to the transport direction 101 (Fig. 2) to abut the (in this example) left edge side 94 of the object 90. In the example shown, the tilt angle a with respect to the horizontal plane 102 is approximately a=30°, without the invention being limited to this and / or the tilt direction shown.

[0065] The tilting causes the object 90 to slide on the support plate 21 in the direction of the lower (here left) edge 23 alone due to gravity, with the left edge side 94 resting against the moving transport surface 31 and thus being transported in the transport direction 101 .

[0066] In the example shown, the support plate 21 , 121 of the conveyor line 100 is continuously tilted with respect to the horizontal plane 102 and is formed with a continuous transport guide 34 with the transport surface 31 at the left edge 23, 123 of the support plate 21 , 121 . Thus, the object 90 is continuously transported along the entire conveyor line 100 through the apparatus 1 according to the invention and, if necessary, further apparatuses 110.

[0067] The width 124 of the support plate 121 of the conveyor line 100 outside the apparatus 1 according to the invention can be (but does not have to be) larger than the width 24 of the support plate 21 in the apparatus 1 according to the invention. Accordingly, with the beginning of the apparatus 1 along the transport direction 101 , there is a transition from a wider support plate 121 in the inspection apparatus 110 to a narrower support plate 21 in the apparatus 1 according to the invention. To illustrate the transition, the support plate 121 outside the apparatus 1 is shown with dots and the support plate 21 inside the apparatus 1 is shown without dots. Apart from the width 24, 124, the support plates 21 , 121 are identically designed in the example shown and are oriented flush with each other at the lower (here left) edge 23, 123 and at their surface facing the object 90. According to the invention, this enables continuous transport of the object 90. Accordingly, the transport surface 31 can be designed to be continuous at the transition to and / or from the apparatus 1 according to the invention. The transport surface 31 and the entire transport guide 34 are therefore provided with uniform reference signs in the figures.

[0068] In the embodiment shown, the support plates 21 , 121 comprise a levitation surface 25 formed as a sonotrode as a spacer element between the surface facing the object 90 and the lower side 92 of the object, which holds the object 90 without physical contact at a gap distance 97 (see Fig. 4) above the support plate 21 , 121 . This reliably prevents mechanical damage to the lower side 92 of the object 90 during transport.

[0069] Sonotrodes are based on acoustic levitation by means of oscillation generators in the support plate 21 , 121 , which generate ultrasonic waves directed transversely to the direction of the transport plane 20 and emit them into the gap 96 (typically an air gap) between the support plate 21 , 121 and the object 90. The sound waves counteract the force of gravity and keep the object 90 hovering above the support plate 21 , 121 . This has already been described in detail at the beginning. Reference is made to this, also with regard to optional features that can also be realized in this embodiment example.

[0070] As shown in Fig. 1 , an apparatus 1 according to the invention for inspecting the right and left edge sides 93, 94 of the object 90 comprises an inspection device 5 for each of the edge sides 93, 94. Each inspection device 5 is formed with an imaging unit 50, which is also referred to as a camera, and a microscope optics 51 , and is equipped with an illumination unit 52 comprising a bright field illumination 53 and a dark field illumination 54. Each inspection device 5 is enclosed as a structural unit in a closed housing 55, in which only the front side facing the support plate 21 is open. In the figures, each of the upper sides is shown open to illustrate the internal structure of the inspection device 5.

[0071] To differentiate between the (technically identical) inspection devices 5 on the right edge 22 of the support plate 21 and on the left edge 23 of the support plate, these are also referred to as right inspection device 62 and left inspection device 63.

[0072] As can be seen in particular from the enlarged Fig. 2, the right inspection device 5, 62 is arranged in front of the right edge 22 of the support plate 21 such that the right edge side 93 of the object 90 transported by the transport surface 31 is moved through the imaging area 56 of the microscope optics 51 (and thus also of the imaging unit 50) of the right inspection device 5, 62. Accordingly, the left inspection device 5, 63 is arranged in front of the left edge 23 of the support plate 21 such that the left edge side 94 of the object 90 transported by the transport surface 31 is moved through the imaging area 56 of the microscope optics 51 (and thus also of the imaging unit 50) of the left inspection device 5, 63.

[0073] For the imaging area 56 of each of the inspection devices 5 being located in front of the right and left edges 22, 23 of the support plate in the areas of the right and left edge sides 93, 94 of the object 90 which are to be inspected, the width 24 of the support plate 21 in the area of the apparatus 1 essentially corresponds to the width 95 of the object 90 in accordance with the invention.

[0074] In order to avoid reflections of the light emitted by the illumination unit 52 with the bright field illumination 53 and the dark field illumination 54 into the imaging unit 50, the support plate 21 of the transport device 2 comprises a first recess 26 in the edge 22, 23 of the support plate 21 facing the respective inspection device 5, 62, 63 at the imaging area 56 of the right and left inspection devices 5, 62, 63 respectively. For this purpose, the first recess 26 is V-shaped , wherein, according to the invention, the intersection point of the V-legs engages deepest into the support plate 21 and, with respect to the length of the imaging area 56 in the transport direction 101 , preferably lies in the center of the imaging area 56, in which the optical axis of the imaging unit 50 preferably also lies.

[0075] According to the invention, the first recess 26 avoids or at least considerably minimizes reflection of light reflected at the support plate 21 into the imaging unit 50. In addition, the edge of the support plate 21 set back in the first recess 26 is not in the depth of field range of the imaging unit and is thus imaged out of focus, which facilitates image evaluation for the edge sides 93, 94 of the object 90 that are imaged in focus. The shape of the first recess 26 is not limited to the V-shape shown here. Other suitable shapes can also be selected for the recess. The edge 27 of the support plate 21 can, for example, be matted and / or inclined to further reduce reflections.

[0076] The right and left inspection devices 5, 62, 63 are arranged on the right and left edges 22, 23 of the support plate 21 opposite each other at the same position with respect to the transport direction 101. This makes the apparatus 1 according to the invention particularly compact in the transport direction 101. In addition, the inspection devices 5, 62, 63, each of which is arranged in a reflection optical system, can also be operated in a transmission optical system in such arrangement, in that light from the illumination unit 52 of one inspection device 5 is coupled into one of the edge sides 92, 93 of the object 90 and the opposite edge side 93, 92 is imaged with the opposite inspection device 5.

[0077] Because the transport guide 34 with the transport surface 31 is arranged on the left edge side 94 of the object 90 in front of the edge side 94, in this embodiment it is provided according to the invention that the transport surface 31 (and with it the entire transport guide 34) comprises a second recess 36 in the region of the first recess 26 of the support plate 21 , at which the left inspection device 5, 63 is arranged. The inspection device 5, 63 is arranged such that the microscope optics 51 optically gathers the imaging area 56 through the second recess 36 and the bright field illumination 53 illuminates the imaging area 56 through the second recess 36.

[0078] This is explained in more detail below with reference to Fig. 3, which shows an enlarged view of Fig. 1 with the apparatus 1 according to the invention essentially in a top view. The second recess 36 in the transport surface 31 is formed by the conveyor belt 32 being interrupted in the region of the second recess 36, in that in the transport direction 101 in front of and behind the second recess 36, each of a first conveyor belt 32 in front of the second recess 36 and a second conveyor belt 32 behind the second recess 36 is provided with a deflecting pulley, of which only the axes 33 are visible in Fig. 3.

[0079] Together, the first conveyor belt 32 and the second conveyor belt 32 form a conveyor belt 32 of the transport device 2 of the apparatus 1 in the area of the inspection devices 5, 62, 63. The spacing of the deflecting pulleys is such that the microscope optics 51 optically gathers the imaging area 56 through the second recess 36 between the deflecting pulleys with the conveyor belt 32 circulating thereon. The same applies to the confocal bright field illumination 53, which illuminates the imaging area 56 through the second recess 36. The length 37 of the second recess in the transport direction 101 at its narrowest point corresponds in the example shown to approximately or at least twice the length of the imaging area in transport direction 101. This enables interference-free imaging with the microscope optics 51 and interference-free bright field illumination.

[0080] Between a plane formed by the axes 33 of the pulleys and the imaging area 56, the second recess 36 widens due to the cylindrical shape of the deflecting pulleys. The length 38 of the second recess 36 in the transport direction 101 at the area of the transport surface 31 facing the support plate 21 corresponds in the example shown to approximately or at least three or four times the length of the imaging area 56 in the transport direction 101 . According to the invention, this widening of the second recess 36 serves for the light irradiation of the dark field illumination 54, which is arranged above and below the transport plane 20 and illuminates the imaging area 56 accordingly in grazing light. The dark field illumination 54 arranged below the transport plane 20 irradiates through the recess 26 in the support plate 21 into the imaging area 56. This applies to the left and right inspection devices 5, 62, 63. According to the invention, the left inspection device 5, 63 is arranged in front of the left edge 23 of the support plate 21 such that the dark field illumination 54 is arranged above and below the transport guide 34 or transport surface 31 and illuminates the imaging area 56 from above and from below through the widening of the second recess 36.

[0081] The length of the first recess 26 in the transport direction 101 at the edge 22, 23 of the support plate 21 is larger than the corresponding width 38 of the second recess 36 at the area of the transport surface 31 facing the support plate 21 .

[0082] The specified minimum dimensions for the length of the recesses 26, 36 generally include preferred embodiments according to the invention. However, the invention is not limited to this.

[0083] Fig. 4 shows a schematic view of the left side of the apparatus 1 without inspection devices 5, 62, 63 with the transported object 90 in a sectional excerpt. The support plate 21 is shown with a view of the left edge 23 with the first recess 26 and the surfaces 27 of the V-shaped first recess 26. In the transport direction 101 , the first recess extends over a length 28.

[0084] On its surface facing the object 90, the support plate 21 forms a levitation surface 25 designed as a sonotrode, which emits ultrasonic waves in the direction of the object 90. A positive pressure is thereby formed between the levitation surface 25 and the lower side 92 of the object, which holds the object 90 in a gap 96 with a gap distance 97.

[0085] In viewing direction in front of the support plate 21 and the object 90, the transport surface 31 is arranged with the transport guide 34, which on principle block the view on the support plate 21 and the object 90, but are shown here only as a dashed transparent frame for illustration. In the section in which the left inspection device 5, 63 is arranged in front of the left edge 23 of the support plate 21 , the second recess 36 is formed in the transport surface 31 , through which the imaging unit 50 optically gathers the imaging area 56. The length 37 of the second recess 36 at its narrowest point between the transport surfaces 31 in the transport direction 101 corresponds approximately to at least twice the imaging area 56.

[0086] The height of the imaging area 56 includes the edge side 94 of the object 90 to be inspected, the gap 96 and, if applicable, at least partially the surface 27 of the support plate 21 in the first recess 26. This also corresponds approximately to the height of a transport plane 20, which is not to be understood as a plane in the mathematical sense and may also have a height range in addition to a surface extension.

[0087] List of reference symbols

[0088] 1 Apparatus

[0089] 2 Transport device

[0090] 20 Transport plane

[0091] 21 Support plate

[0092] 22 Right edge of the support plate

[0093] 23 left edge of the support plate

[0094] 24 Width of the support plate

[0095] 25 Levitation surface designed as a sonotrode

[0096] 26 First recess

[0097] 27 Surface in the first recess

[0098] 28 Length of first recess in transport direction

[0099] 31 Transport surface

[0100] 32 Conveyor belt

[0101] 33 Axles of guiding pulleys / deflecting pulleys 34 Transport guide

[0102] 36 Second recess

[0103] 37 Length of the second recess at its narrowest point

[0104] 38 Length of the second recess at the transport surface

[0105] 5 Inspection device

[0106] 50 Imaging unit

[0107] 51 Microscope optics

[0108] 52 Illumination unit

[0109] 53 Confocal bright field illumination

[0110] 54 Dark field illumination

[0111] 55 Housing

[0112] 56 Imaging area

[0113] 62 Left inspection device

[0114] 63 Right inspection device

[0115] 90 Object

[0116] 91 Upper side of the transported object

[0117] 92 Lower side of the transported object

[0118] 93 Right edge side of the transported object

[0119] 94 Left edge side of the transported object

[0120] 95 Width

[0121] 96 Gap

[0122] 97 Gap distance

[0123] 100 Conveyor line

[0124] 101 Transport direction

[0125] 102 Horizontal plane

[0126] 110 Inspection apparatus

[0127] 121 Support plate Right edge of the support plate Left edge of the support plate Width of the support plate Inspection device

Claims

Claims1 . Apparatus for inspecting two opposite right and left edge sides (93, 94), relative to a transport direction (101 ), of a transported planar object (90), wherein the right and left edge sides (93, 94) of the object (90) connect an upper side (91 ) and a lower side (92) of the object (90) and wherein the surfaces of the left and right edge sides (93, 94) are oriented parallel to the transport direction (101 ), wherein the apparatus (1 ) comprises a transport device (2) for moving the object (90) transported in the transport direction (101 ) with a support plate (21 ) aligned parallel to the lower side (92) of the object (90) in a transport plane (20) of the transport device (2), wherein the width (24) of the support plate (21 ) between a right edge (22) and a left edge (23) of the support plate (21 ) relative to the transport direction (101 ) essentially corresponds to a width (95) of the object (90) between the right and left edge sides (93, 94), and with at least one transport surface (31 ) which engages at the object (90) and moves the object (90) in the transport direction (101 ), wherein the apparatus (1 ) for inspecting the right and left edge sides (93, 94) of the object (90) respectively comprises an inspection device (5) with an imaging unit (50) comprising a microscope optics (51 ) and an illumination unit (52) comprising a bright field illumination (53) and / or a dark field illumination (54), wherein a right inspection device (5, 62) is arranged in front of the right edge (22) of the support plate (21 ) such that the right edge side (93) of the object (90) transported by the transport surface (31 ) is moved through an imaging area (56) of the microscope optics (51 ) of the right inspection device (5, 62), and wherein a left inspection device (5, 63) is arranged in front of the left edge (94) of the support plate (21 ) such that the left edge side (94) of the object (90) transportedby the transport surface (21 ) is moved through an imaging area (26) of the microscope optics (51 ) of the left inspection device (5, 63), characterized in that the support plate (21 ) of the transport device (2) has at each imaging area (56) of the right and left inspection devices (5, 62, 63) a first recess (26) in the edge (22, 23) of the support plate (21 ) facing the respective inspection device (5, 62, 63) , wherein each first recess (26) is shaped such that the width (24) of the support plate (21 ) between its right edge (22) and its left edge (23) is reduced in the region of the recess (26).

2. The apparatus according to claim 1 , characterized in that the imaging unit (50) and the illumination unit (52) of the inspection device (5, 62, 63) are arranged in a reflection arrangement.

3. The apparatus according to claim 1 or 2, characterized in that the right and left inspection devices (5, 62, 63) are arranged on the right and left edges (22, 23) of the support plate (21 ) opposite each other at the same position with respect to the transport direction (101 ).

4. Apparatus according to one of the preceding claims, characterized in that the bright field illumination (53) of the illumination unit (52) is designed as confocal illumination with the microscope optics (51 ) and / or the dark field illumination (54) is arranged above and / or below the transport plane (20) of the transport device (2) and is directed towards the imaging area (56).

5. Apparatus according to one of the preceding claims, characterized in that the support plate (21 ) comprises at least one spacer element (25) whichholds the lower side (92) of the transported object (90) at a gap distance (97) from the support plate (21 ).

6. The apparatus according to claim 5, characterized in that a plurality of spacer elements are provided and at least one of the spacer elements forms a driven transport surface.

7. The apparatus according to claim 5, characterized in that the support plate (21 ) comprises a levitation surface (25) as the spacer element, which holds the object (90) above the support plate (21 ) without physical contact at the gap distance (97).

8. The apparatus according to claim 7, characterized in that the levitation surface (25) is designed as a sonotrode.

9. Apparatus according to one of the preceding claims, characterized in that the support plate (21 ) is tilted transversely to the transport direction (101 ) with respect to a horizontal plane (102) and in that the transport surface (31 ) is designed protruding from the support plate (21 ) in the direction of the transport plane (20) and directed parallel to the transport direction (101 ) to abut one of the right or left edge sides (93, 94), wherein the transport surface (31 ) comprises a second recess (36) in the region of the first recess (26) of the support plate (21 ), at which one of the inspection devices (5, 63) is arranged.

10. Apparatus according to claim 9, characterized in that the dark field illumination (54) is arranged above and below a transport guide (34) of the transport surface (31 ).11 . Apparatus according to one of the preceding claims, characterized in that the transport surface (31 ) is designed as part of a conveyor belt (32) rotating on guiding pulleys.

12. Apparatus according to one of claims 1 to 8, characterized in that the transport surface is designed as a suction surface embedded in the support plate for generating a negative pressure and fixes the transported object, wherein the suction surface is movable relative to the support plate in the transport direction.

13. Apparatus according to one of the preceding claims, characterized in that the right and / or left inspection device (5, 62, 63) arranged in the transport plane (20) is oriented with an optical axis of the inspection device (5, 62, 63) such that the optical axis runs perpendicular to the surface of the right and / or left edge side (93, 94).

14. Apparatus according to one of the preceding claims, characterized in that the apparatus (1 ) comprises a control device which is adapted to control the inspection devices and / or the transport device.

15. Use of an apparatus according to any one of claims 1 to 14 for inspecting two opposite right and left edge sides (93, 94), with respect to a transport direction (101 ), of a transported planar object (90).

Images