COMPONENT CONVEYING INSTRUMENT WITH AN ADJUSTING UNIT AND METHOD OF ADJUSTING A COMPONENT CONVEYING INSTRUMENT

Abstract

A component conveying instrument comprising a first and second conveying instrument for conveying a component. The first conveying instrument is arranged to transfer the component to the second conveying instrument at a transfer location. The component conveying instrument further comprises an adjustment unit for adjusting one of the conveying instruments relative to the other conveying instrument along at least one or about at least one adjustment axis and an imaging unit. The imaging unit captures at least one image of the transfer location showing an end region of the first conveying instrument, and an end region of the second conveying instrument. The component conveying instrument also comprises an analyzing unit for analyzing the image, where the analyzing unit is coupled to the adjusting unit and is adapted to determine an asymmetry measure between the end region of the first conveying instrument and the end region of the second conveying instrument.

Claims

1. A component conveying device, comprising: a first conveying instrument for conveying a component; a second conveying instrument for conveying the component; wherein the first conveying instrument is arranged to transfer the component to the second conveying instrument at a transfer location; an adjustment unit for adjusting one of the first or second conveying instruments relative to the other conveying instrument along at least one or about at least one adjustment axis; a first imaging unit configured to record at least one image of the transfer location that shows at least one end region of the first conveying instrument in a first section and at least one end region of the second conveying instrument in a second section; and an analysis unit, coupled to the adjustment unit, for analyzing the at least one image, which analysis unit is set up to determine from the at least one image a measure of an asymmetry between the end region of the first conveying instrument and the end region of the second conveying instrument, said adjustment unit being configured to adjust at least one of the conveying instruments with respect to the other conveying instrument along the at least one adjustment axis or about the at least one adjusting axis as a function of the determined asymmetry measure.

2. The component conveying device according to claim 1, wherein the analysis unit is adapted to use a mirror axis, which is either oriented perpendicular to a transfer path of the component or coincides with the transfer path, for determining the asymmetry measure between the end region of the first conveying instrument and the end region of the second conveying instrument.

3. The component conveying device according to claim 2, wherein the analysis unit is adapted to determine, for the asymmetry measure (a) to detect a grey value for each pixel on one side of the mirror axis, (b) to determine the mirrored pixel for the pixel under consideration with the mirror axis in each case and to detect its grey value, (c) determining in each case a difference value which represents a measure of the difference between the grey value of the pixel and the grey value of the mirrored pixel, and (d) to sum up all difference values determined in this way, wherein the sum formed in step (d) determines the asymmetry measure to the image.

4. The component conveying device according to claim 2, wherein the analysis unit is adapted to determine, for the image, the measure of asymmetry by (a) creating a mirror image, which is generated by a reflection around a mirror axis, which is at least approximately parallel to the transfer path, (b) acquiring the grey values for each pixel of the image and the corresponding pixel of the mirror image, (c) determining in each case a difference value which represents a measure of the difference between grey value of the image point and the grey value of the corresponding image point of the mirror image, (d) summing up all the difference values determined in this way, (e) producing at least one further mirror image by moving the mirror image produced in step (a) in a direction perpendicular to the mirror axis, and (f) repeating steps (b) to (d) using the at least one further mirror image, wherein the respective sums produced in step (d) are compared and the minimum of the sums determines the asymmetry measure for the image concerned.

5. The component conveying device according to claim 1, said device being arranged to perform the following steps: (i) acquiring a first image with the first imaging unit; (ii) determining the asymmetry measure of the first image by the analysis unit; (iii) adjusting one of the conveying instruments relative to the other conveying instrument in a first direction by the adjusting unit; (iv) acquiring a second image with the first imaging unit; (v) determining the asymmetry measure of the second image by the analysis unit; (vi) comparing the asymmetry measure of the second image with the asymmetry measure of the first image by the analysis unit; (vii) if the asymmetry measure of the second image is smaller than the asymmetry measure of the first image further moving the one conveying instrument with respect to the respective other conveying instrument in the first direction by the adjusting unit; and if the asymmetry measure of the second image is greater than or equal to the asymmetry measure of the first image moving one conveying instrument with respect to the other conveying instrument in a second direction opposite to the first direction by the adjusting unit.

6. The component conveying device according to claim 5, said device being arranged for subsequently carrying out the following further steps: (viii) acquiring a third image with the first imaging unit; (ix) determining the asymmetry measure of the third image by the analysis unit; (x) comparing the asymmetry measure of the third image with the asymmetry measure of the second image by the analysis unit; (xi) if the asymmetry measure of the third image is smaller than the asymmetry measure of the second image: further moving the one conveying instrument with respect to the respective other conveying instrument in the direction of the last moving by the adjusting unit; and if the asymmetry measure of the third image is greater than or equal to the asymmetry measure of the second image: moving one conveying instrument with respect to the other conveying instrument concerned in the opposite direction to the direction of the last movement by the adjusting unit.

7. The component conveying device according to claim 1, wherein the first conveying instrument and/or the second conveying instrument is formed by a pipette or an ejector or a pick-up having a suction contact point.

8. The component conveying device according to claim 2, wherein the first conveying instrument and/or the second conveying instrument is part of a conveying apparatus which is mounted so as to be linearly movable along an axis and/or rotatable about an axis of rotation, which is mounted so as to be linearly movable along an axis and/or rotatable about an axis of rotation, wherein by means of a presetting movement of the conveying apparatus along the axis or about the axis of rotation the respective conveying instrument can be moved into a transfer position provided for the transfer of the component along the transfer path; wherein the adjusting unit is adapted to move the respective conveying instrument along the axis and/or to rotate about the axis of rotation for adjusting the transfer position of the respective conveying instrument.

9. The component conveying device according to claim 7, wherein the first conveying instrument is a turning device on a linear axis.

10. The component conveying device according to claim 1, wherein the adjustment axis makes an angle with a main axis of the first conveying instrument which is between 70° and 110°.

11. The component conveying device according to claim 1, wherein a direction from the first imaging unit to the transfer location includes an angle with a main axis of the first conveying instrument that is between 70° and 110°.

12. The component conveying device according to claim 1, further comprising a second imaging unit adapted to capture at least one image of the transfer location, which in a first portion of the at least one image captured by the second imaging unit shows at least one end region of the first conveying instrument and in a second portion of the at least one image captured by the second imaging unit shows at least one end region of the second conveying instrument, wherein a direction from the second imaging unit to the transfer location differs from a direction from the first imaging unit to the transfer location.

13. The component conveying device according to claim 12, wherein the analysis unit is further adapted to analyze the at least one image captured by the second imaging unit and determine a further asymmetry measure between the end region of the first conveying instrument and the end region of the second conveying instrument; wherein the adjusting unit is arranged to adjust at least one of the conveying instruments relative to the respective other conveying instrument along or about a further adjustment axis in dependence on the determined further measure of asymmetry.

14. A method for using a component conveying device having a first conveying instrument for conveying a component and a second conveying instrument for conveying the component, wherein the first conveying instrument is configured to transfer the component to the second conveying instrument at a transfer location, comprising the steps: (ii) acquiring a first image of the transfer location with an imaging unit; (iii) determining an asymmetry measure of the first image by a unit analysis; (iv) adjusting one of the conveying instruments relative to the other conveying instrument in a first direction by means of a setting unit; (v) acquiring a second image of the transfer location with the imaging unit; (vi) determining an asymmetry measure of the second image by the unit analysis; (vii) comparing the asymmetry measure of the second image with the asymmetry measure of the first image by the analysis unit; (viii) wherein if the asymmetry measure of the second image is smaller than the asymmetry measure of the first image further adjusting the one conveying instrument with respect to the respective other conveying instrument in the first direction by the adjusting unit; and (ix) if the asymmetry measure of the second image is greater than or equal to the asymmetry measure of the first image: (x) adjusting one of the conveying instruments relative to the other conveying instrument in a second direction opposite to the first direction by the adjusting unit.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0064] Further features, characteristics, advantages and possible variations will become clear to a person skilled in the art from the following description, in which reference is made to the accompanying drawings. In this respect, the figures schematically show variants of a component conveying instrument, without limiting the variants of the described device to the latter.

[0065] FIG. 1 shows a perspective sketch of a component conveying device with a transfer location between a first conveying instrument and a second conveying instrument.

[0066] FIG. 1a shows a detail from FIG. 1 around the transfer location.

[0067] FIGS. 2a to 2k schematically show images of the transfer location taken with an imaging unit of the component conveying device, wherein the second conveying instrument is adjusted in different ways with respect to the first conveying instrument.

[0068] FIG. 2l shows a diagram representing asymmetry measures of the images outlined in FIGS. 2a to 2k.

[0069] FIG. 3 shows a principle sketch of an image of the transfer location captured by the imaging unit.

[0070] FIGS. 4a to 4c show schematic images of the transfer location exemplary for differently shaped conveying instruments.

[0071] FIGS. 5a and 5b show a flow diagram for a setting method for a component conveying instrument.

DETAILED DESCRIPTION OF THE EMBODIMENTS

[0072] FIG. 1 shows a perspective sketch of a component conveying instrument 100. The component conveying instrument 100 comprises a first conveying instrument 101 with a first conveying instrument F1 for conveying an electronic component and a second conveying instrument 102 with a second conveying instrument F2 for conveying the component. In the example shown, the two conveying instruments F1, F2 are so-called pick-ups. FIG. 1a shows an area around the two conveying instruments F1, F2 in more detail.

[0073] The transfer the component at a transfer location ÜS along an intended transfer path W to the second conveying instrument F2. In this case, the first conveying instrument F1 has a main axis H.sub.0 along which at least a section of the intended transfer path W runs.

[0074] The first conveying instrument 101 is a turning device which is mounted movably relative to a housing (not shown in FIG. 1) of the component conveying instrument 100, so that it can be moved linearly along an axis and can be rotated about an axis of rotation. In the illustration of FIG. 1, the y-axis of a Cartesian coordinate system is selected as the axis and as the axis of rotation. The linear movement option is indicated by a first arrow P1, the rotary movement option by a curved second arrow P2. A control system of the component conveying instrument 100 (not shown in the figure) is used to move the first conveying instrument 101.

[0075] The first conveying instrument 101 further comprises another conveying instrument arranged opposite the first conveying instrument F1 with respect to the y-axis. In a variant not shown, the first conveying instrument 101 comprises more than two conveying instruments, for example four or eight corresponding conveying instruments arranged uniformly around the y-axis.

[0076] By rotating the first conveying instrument 101 about the y-axis, the first conveying instrument F1 is rotated about the y-axis so that it can be brought into different positions. Thereby, a transfer position, outlined in FIG. 1, is provided for transferring the component from the first conveying instrument F1 to the second conveying instrument F2 at the transfer location ÜS. A pick-up position of the first conveying instrument F1, which is opposite the transfer position with respect to the y-axis, for example, is provided for picking up the component from a structured component supply 103, such as a wafer.

[0077] The second conveying instrument 102 is a linear axis that is mounted for movement relative to the housing, such that it can be moved along the y-axis and along the x-axis by the controller. By moving the second conveying instrument 102 along the x-axis and/or along the y-axis, the second conveying instrument F2 is moved to different positions. A transfer position, outlined in FIG. 1, is provided for transferring the component from the first conveying instrument F1 to the second conveying instrument F2 at the transfer location ÜS. The second conveying instrument 102 may deposit the component at a deposit location in or on a receiving device (not shown). Such a receiving device may be, for example, a (wafer) table providing a receiving substrate or a component belt having receiving pockets for components.

[0078] For a safe transfer of the component from the first conveying instrument F1 to the second conveying instrument F2, an exact alignment of the first conveying instrument F1 and the second conveying instrument F2 is required. Otherwise, there is a risk that the component will fall during the transfer.

[0079] For this purpose, the component conveying instrument 100 further comprises an adjustment unit with which one of the two conveying instruments F1, F2 can be set or adjusted relative to the respective other conveying instrument along at least one or around at least one adjustment axis. For adjustment, the two conveying instruments F1, F2 are accordingly first brought into their respective transfer position by presetting. Subsequently, a fine adjustment or adjustment of the mutual alignment of the two conveying instruments F1, F2 is carried out with the aid of the adjustment unit.

[0080] In other words, the adjusting device is used to adjust at least one of the two transfer positions so that the two conveying instruments F1, F2 are thereby precisely aligned with each other. In the example shown, the transfer position of the first conveying instrument F1 can be adjusted or set with the adjusting unit by moving the first conveying instrument 101 along the y-axis or by rotating the first conveying instrument 101 about the y-axis. The transfer position of the second conveying instrument F2 can be adjusted with the adjusting unit by moving the second conveying instrument 102 along the x-axis and/or by moving the second conveying instrument 102 along the y-axis.

[0081] Further, the second conveying instrument 102 may also be moved along the z-axis by the controller.

[0082] In a variant not shown, the second conveying instrument 102 is designed as a further turning device which corresponds in structure to the first-mentioned turning device, but the axis of rotation of the further turning device encloses an angle of more than 0° with the axis of rotation of the first-mentioned turning device, i.e. the y-axis. In one variant, the axis of rotation of the further turning device is the x-axis. In a further variant not shown, the axis of rotation of the first reversing device and the second reversing device is the y-axis.

[0083] Furthermore, the component conveying instrument 100 has an imaging unit K1 which is set up to record at least one image of the transfer location ÜS, sketched by way of example in FIG. 3, which image shows at least one end region E1 of the first conveying instrument F1 in a first section H1 of the image, and at least one end region E2 of the second conveying instrument in a second section H2 of the image. In FIG. 3, the main axis of the first conveying instrument F1 is sketched, along which at least a section of the aforementioned transfer path W runs.

[0084] Furthermore, the component conveying instrument 100 has an—analysis unit, coupled to the adjustment unit, for analyzing the at least one image, which analysis unit is set up to determine, for the at least one image, a measure of an asymmetry between the end region E1 of the first conveying instrument F1 and the end region E2 of the second conveying instrument F2—in short, an asymmetry-measure. The adjustment unit is set up to adjust the first conveyor instrument F1 relative to the second conveying instrument F2 along the adjustment axis—in this case the y-axis—as a function of the determined asymmetry measure.

[0085] The following describes the steps for setting or adjusting the—mutual alignment of the two conveying instruments F1, F2.

[0086] After the two conveying instruments F1, F2 have been brought into their respective transfer positions by moving the two conveying instruments 101, 102 accordingly, the following steps are carried out in the order indicated: [0087] (i) acquiring a first image with the imaging unit K1, [0088] (ii) determining the asymmetry measure of the first image by the analysis unit; [0089] (iii) adjusting one of the two conveying instruments, here exemplarily the second conveying instrument F2 with respect to the respective other conveying instrument F1 in a first direction, here exemplarily the y-direction by the adjusting unit; [0090] (iv) acquiring a second image with the imaging unit K1, [0091] (v) determining the asymmetry measure of the second image by the analysis unit; [0092] (vi) comparing the asymmetry measure of the second image with the asymmetry measure of the first image by the analysis unit; [0093] (vii) of the asymmetry measure of the second image is smaller than the asymmetry measure of the first image: further adjustment of the second conveying instrument F2 relative to the first conveying instrument F1 in the y-direction by the adjusting unit; and if the asymmetry measure of the second image is greater than or equal to the asymmetry measure of the first image: adjustment of the second conveying instrument F2 relative to the first conveying instrument F1 in a second direction opposite to the y-direction, i.e. in the “−y” direction, by the adjusting unit.

[0094] In this way, the second conveying instrument F2 is brought closer to the desired aligned orientation.

[0095] The steps can then be repeated using additional images until a desired precision of mutual alignment of the two conveying instruments F1, F2 is achieved.

[0096] If the first conveying instrument F1 is adjusted in relation to the second conveying instrument F2, the result is completely analogous.

[0097] In FIGS. 2a to 2k, on the basis of corresponding images B1, B2, B3 . . . B11 of the transfer location ÜS taken with the imaging unit K1, an exemplary and highly simplified case is sketched in which the second conveying instrument F2 is appropriately adjusted several times.

[0098] On the left side of FIG. 2a, the first image B1 is sketched. The end region E1 of the first conveying instrument F1, also referred to here by way of example as a “pipette”, and correspondingly the end region E2 of the second conveying instrument F2 and the mirror axis SA can be seen by black marking on a white background. In addition, the main axis H.sub.0 of the first conveying instrument F1 is sketched.

[0099] After acquiring the first image B1 in step (i) above, the associated asymmetry measure for the first image B1 is determined in step (ii), referred to herein as the first asymmetry measure A1. The manner in which an asymmetry measure for an image is determined is discussed in more detail below.

[0100] In step (iii), starting from the start situation shown in FIG. 2a, the second conveying instrument F2 is adjusted in a first direction, here exemplarily to the right, by a small adjustment amount. Then, in step (iv), the second image B2 shown in FIG. 2b is acquired. In the example shown, the rightward adjustment is made by the width of one pixel, as indicated by “1 pix->” in the upper left of FIG. 2b. In general, the small adjustment dimension can be, for example, a fraction of a millimeter and is—basically freely selectable depending on the desired accuracy of the adjustment.

[0101] Then, in step (v), the second asymmetry measure A2 is determined for the second image B2 in a corresponding manner.

[0102] In step (vi), the first asymmetry measure A1 and the second asymmetry measure A2 are then compared. In the example shown—as will be—explained in more detail below—the second asymmetry measure A2 is the same size as the first asymmetry measure A1.

[0103] In step (vii), two cases are distinguished. If the second asymmetry measure A2 is greater than or equal to the first asymmetry measure A1, that is, if, as here, the case A2≥A1 holds, in a next step, the second conveying instrument F2 is adjusted in the opposite direction. Thus, the situation outlined in FIG. 2c is obtained. This is continued—as exemplarily sketched with reference to FIGS. 2i and 2j—the asymmetry dimension becomes larger again. Thus, if after an adjustment the asymmetry measure increases again, an adjustment of the second conveying instrument F2 in the opposite direction takes place. In this way, a relative setting of the two conveying instruments F1, F2 can be found in which the asymmetry measure has a minimum.

[0104] FIGS. 5a and 5b show a corresponding flow chart: In step S01, the two conveying instruments 101, 102 are moved by presetting so that the two conveying instruments F1, F2 are in their respective transfer positions. In step S02, the first image is acquired and the corresponding asymmetry measure is determined. In step S03, an adjustment of one of the two conveying instruments in a first direction follows. In step S04, a further image is acquired and the associated asymmetry measure is determined. In step S05, it is determined whether the most recently determined asymmetry measure has decreased compared to the immediately previously determined asymmetry measure. In other words, in step S05, it is inquired whether the symmetry has improved by the last adjustment. If this is not the case, an adjustment in the opposite direction takes place in step S06, and in the then following step S04 the acquisition of a further image and the determination of the associated asymmetry measure takes place again.

[0105] However, if it is determined in step S05 that the symmetry has improved, another adjustment in the same direction is performed in step S07. After performing step S07, an image is again acquired in step S08 and the corresponding asymmetry measure is determined. Then, in step S09, it is again determined whether the most recently determined asymmetry measure has decreased in comparison with the asymmetry measure determined immediately before. In other words, in step S09, it is inquired whether the symmetry has improved by the last adjustment. If the symmetry has improved, it goes back to step S07 and another adjustment is again made in the same direction. If it is determined in step S09 that the symmetry has not improved, an adjustment is made in the opposite direction in step S10, using a now smaller adjustment dimension.

[0106] In step S11, an image is again acquired and the associated asymmetry measure is determined. In step S12, it is determined again whether the last determined asymmetry measure has decreased in comparison to the asymmetry measure determined immediately before. If yes, it goes back to step S10 and a further adjustment is made. If no, using the imaging unit K1 is completed at step S13. The determined adjustment values are stored in a memory coupled to the control unit. In a subsequent use of the component conveying instrument 100, the setting values can be used by the controller and the setting unit when the two conveying instruments F1, F2 are moved to their transfer positions by appropriately moving the conveying instruments 101, 102.

[0107] The following describes how, according to a first example, the asymmetry measure for an image is determined by the analysis unit.

[0108] The analysis unit is set up to use a mirror axis SA for determining the asymmetry dimension, which—as sketched in FIG. 3 and also in FIG. 2a—is oriented perpendicular to the intended transfer path W. The mirror axis SA preferably intersects the transfer path W in its geometric center M. Preferably, the mirror axis SA intersects the transfer path W in its geometric center M.

[0109] Referring now to FIG. 2a, the steps performed by the analysis unit to determine the asymmetry measure A1 for the first image B1 are explained. The image B1 has a first section H1 in which the end region E1 of the first conveying instrument F1 is shown, and a second section H2 in which the end region E2 of the second conveying instrument F2 is shown. Here, the first section H1 extends below the mirror axis SA and the second section H2 extends above the mirror axis SA.

[0110] The first image B1 is composed of many pixels B.sub.1, B.sub.2, B.sub.3, . . . , each pixel having a certain grey value. In FIG. 2a, the second section H2 of the image B1 comprises a total of 160 pixels which are arranged in ten rows and sixteen columns. The grey value “1” is selected for black and the grey value “0” for white.

[0111] In a step (a), for each pixel B.sub.1, B.sub.2, B.sub.3, . . . B.sub.160 above the mirror axis SA, the respective grey value is detected.

[0112] In step (b), for each of these pixels B.sub.1, B.sub.2, B.sub.3, . . . B.sub.160, a mirrored pixel B.sub.1′, B.sub.2′, B.sub.3′, . . . B.sub.160′ is determined using the mirror axis SA and its grey value is detected. The mirrored pixels B.sub.1′, B.sub.2′, B.sub.3′, . . . B.sub.160′ are accordingly located below the mirror axis SA.

[0113] In step (c), a difference value Δ.sub.1, Δ.sub.2, Δ.sub.3, . . . Δ.sub.160 is determined for each of the pixels B.sub.1, B.sub.2, B.sub.3, . . . B.sub.160, respectively, by forming a difference between the grey value of the pixel B.sub.i in question and the grey value of the pixel B.sub.i′ in question which is mirrored, and then squaring the difference. The difference values Δ.sub.i thus obtained are indicated on the right in FIG. 2a in a corresponding grid.

[0114] In step (d), all the difference values Δ.sub.1, Δ.sub.2, Δ.sub.3, . . . Δ.sub.160 determined in this way are added up. In the example shown in FIG. 2a, this sum ΣΔ.sub.i results in value “72”, as indicated on the right in FIG. 2a.

[0115] Here, the sum ΣΔ.sub.i formed in step (d) is selected as the asymmetry measure to the image in question. Thus, the asymmetry measure A1 of the first image B1 shown in FIG. 2a has the value 72.

[0116] In the sixth image B6 shown in FIG. 2f, the asymmetry measure A6 has the value 44. Illustratively and simplified, “folding” the first conveying instrument F1 about the mirror axis SA results in an overlap area with the second conveying instrument F2 in which the difference values are zero. The larger this overlap area, the better the symmetry and thus the more aligned. In this way, as the overlap area increases, the asymmetry measure decreases.

[0117] In FIG. 2l, the asymmetry measures A1 to A11 of the eleven images B1 to B11 shown correspondingly in FIGS. 2a to 2k are plotted in a diagram.

[0118] According to a second example, the asymmetry measure may be determined using a mirror axis coinciding with the intended transfer path W, that is, with the major axis H of .sub.0the first conveying instrument F1.

[0119] As can be seen from a plausibility consideration based on FIG. 3, the fact that here the mirror axis coincides with the main axis H.sub.0 means that the first conveying instrument F1 or its end region E1 is ideally aligned symmetrically to the mirror axis. If the second conveying instrument F2 has an offset with respect to the mirror axis, mirroring second conveying instrument F2 does not result in an overlap region in the sense mentioned above, or only in a very small overlap region and thus in a high value for the asymmetry dimension. If, however, the second conveying instrument F2 is ideally aligned, this results in a maximum overlap area and thus a minimum value for the asymmetry dimension.

[0120] Therefore, the above calculation steps can also be carried out in an analogous manner in this case.

[0121] According to a third example, the asymmetry measure can be determined by the following steps [0122] (a) A mirror image is created for the image in question, which is generated by a reflection about a mirror axis parallel to the path of motion W, [0123] (b) for each pixel of the image and the corresponding pixel of the mirror image the grey values are recorded, [0124] (c) then a difference value is determined in each case, which represents a measure of the difference between the grey value of the pixel and the grey value of the corresponding pixel of the mirror image, [0125] (d) all difference values determined in this way are added up, [0126] (e) Subsequently, starting from the image, at least one further mirror image is generated using at least one further mirror axis which is offset perpendicularly to the first-mentioned mirror axis, [0127] (f) Steps (a) to (d) are then repeated using the at least one further mirror image.

[0128] Then, the respective sums created in step (d) are compared and the mini mum of the sums is used as the asymmetry measure to the image in question.

[0129] The more mirror images are used, in general, a greater accuracy can be achieved.

[0130] An advantage of the method described herein is that the adjustment by the adjusting unit can also be carried out in the case of differently shaped conveying instruments, as exemplarily outlined in FIGS. 4a to 4c.

[0131] The variants of the device described above, as well as the structural and operational aspects thereof, are merely intended to provide a better understanding of the structure, operation and characteristics; they do not limit the disclosure to the variants. The figures are partially schematic, with essential features and effects sometimes shown in significantly enlarged form, in order to clarify the functions, operating principles, technical variants and features. In this regard, any—mode of operation, principle, technical variant and feature disclosed in the FIGS. or in the text may be freely and arbitrarily combined with any claim, feature in the text and in the other FIGS., other modes of operation, principles, technical variants and features contained in or resulting from the present disclosure, so that all conceivable combinations are attributable to the described method of operation. Combinations between all individual variants in the text, i.e. in each section of the description, in the claims and also combinations between different variants in the text, in the claims and in the FIGS. are also included. Also, the claims do not limit the disclosure and thus the combinations of all disclosed features with each other. All disclosed features are also explicitly disclosed herein individually and in combination with all other features.