ADJUSTING DEVICE AND ADJUSTING PROCEDURE

Description

[0001] The invention relates to an adjustment device for adjusting an optical element to a light transmitting or light receiving unit of an optoelectronic sensor according to claim 1 and to an adjustment method according to claim 9.

[0002] An optoelectronic sensor, such as a code reader, is used in many areas of everyday life to read information data from an image object, where the image object can be in the form of a one-dimensional or two-dimensional barcode. For this purpose, the optoelectronic sensor has a light emitting and receiving unit arranged on an electronic board. The light emitting unit serves to illuminate a reading area of ​​the sensor, in particular to expose the image object, and the light receiving unit serves to receive light remitted by the image object in order to generate signals from the received light for determining the information data of the image object.

[0003] To improve the transmission and reception performance, an optical element, preferably in the form of a lens, is assigned to the light transmitting and / or receiving unit. This optical element is mounted in an optics carrier and secured to the optics carrier, in particular by gluing or screwing. For this purpose, the optics carrier with the optical element is arranged in a fixed position relative to the light transmitting or receiving unit. The accuracy of the positioning of the optical element in the optics carrier relative to the light transmitting or receiving unit plays a central role in the sensor's performance.

[0004] For this purpose, the optical element must be aligned relative to the light emitting or receiving unit. During alignment, an optimum operating position of the optical element within the optics carrier relative to the light emitting or receiving unit is determined based on an optimum for a suitable measurement parameter, such as the sharpness of a laser spot or a received signal level. The optical element to be aligned is positioned and secured in this operating position. Attachment is preferably achieved using a UV-curing adhesive.

[0005] An adjusted fixation of the optical element in three dimensions represents a complex problem to solve, for example due to distortion of the adhesive during curing. To solve the problem, the degrees of freedom of the optical element can be reduced during adjustment or the adjustment can be divided among different components.

[0006] To reduce the degrees of freedom, for example, the optical element is fixed in a plane using a gripper and moved into the operating position using a high-precision travel axis in a direction perpendicular to the plane. However, the gripper's gripping action can already result in mechanical over-determination, so that play-free holding is not guaranteed. A stable, completely force-free fixation of the optical element to be adjusted is difficult or even impossible to achieve.

[0007] DE 10 2005 046 154 A1 describes a measuring system for inspecting a surface. A measuring head with a sensor can be precisely adjusted / positioned in height (z-direction) across a substrate surface using air bearings. Air exiting through an outlet creates an air cushion on which the measuring head can glide freely over the substrate surface. The strength of the air flow determines the height of the air cushion and thus the vertical distance of the measuring head above the substrate surface. A mechanical surface positioning system allows the measuring head to be additionally positioned in the xy plane relative to the substrate to scan the substrate surface.

[0008] Dividing the degrees of freedom between different components is complex and a certain tolerance is unavoidable, which can result in inaccuracies in the adjustment of the optical element.

[0009] It is therefore an object of the invention to provide an adjustment device for adjusting an optical element relative to a light transmitting or light receiving unit of an optoelectronic sensor, which ensures simple and precise adjustment of the optical element.

[0010] The object is achieved according to the invention by an adjustment device having the features of claim 1.

[0011] Here, the adjustment device for adjusting an optical element relative to a light emitting or light receiving unit of an optoelectronic sensor, wherein the optical element is mounted in a cylindrical optics carrier and the light emitting or light receiving unit is arranged on an electronics card of the sensor, is designed such that the optics carrier can be arranged in a fixed position in a defined position relative to the light emitting or light receiving unit, and that compressed air can be introduced into the optics carrier in order to fix the optical element provided in the optics carrier in the direction of a first and a second degree of freedom within the optics carrier transversely to a longitudinal axis and in order to be able to move the optical element in the direction of the longitudinal axis into a defined operating position without contact, wherein the optical element can be moved along the longitudinal axis of the optics carrier towards the light emitting or light receiving unit or from the light emitting or light receiving unit.Light receiving unit is movable away, so that the optical element can be aligned relative to the light emitting or light receiving unit into the defined operating position and can be fastened in the operating position in which the optical element is adjusted relative to the light emitting or light receiving unit.

[0012] This results in the technical advantage that the optical element is fixed stably and play-free in two directions without mechanical over-determination by the adjustment device, while simultaneously being movable in a third direction perpendicular to the other two degrees of freedom. In this case, the optical element preferably comprises a lens.

[0013] The contactless movement of the optical element advantageously allows both the collimation of the light emitting and receiving units and the angular alignment to be performed simultaneously. The supplied compressed air must be regulated accordingly.

[0014] According to claim 1, at least two grooves are provided on an inner wall of the optics carrier, extending parallel to the longitudinal axis of the optics carrier and designed to conduct the compressed air. Advantageously, the grooves on the inner wall are arranged at equal or unequal distances, particularly angular distances, from one another. This allows for a wide range of uses of the adjustment device, since the grooves can be planned and provided during the manufacture of the optics carrier, allowing different sensor types, particularly those with different optical elements, to be adjusted with the adjustment device.

[0015] Arranging the grooves at equal distances from one another has the advantage that the optical element can be easily centered inside the optics carrier, provided that the open sides of the grooves have the same dimensions so that the air pressure in the grooves exerts the same force on the optical element in each groove. If the grooves are provided at unequal distances from one another on the inner wall of the optics carrier, the air pressure can exert a targeted lateral force on the optical element in order to use a point on the inner wall of the optics carrier as a stop for the optical element to the optics carrier during adjustment. Any distortion of the position of the optical element can be reduced by such a stop.

[0016] Furthermore, according to a further preferred embodiment, at least one recess is provided along a groove, which has a larger cross-sectional area and thus a larger contact surface for the air pressure than the groove. This results in the advantage that, due to the larger contact surface, a greater compressive force is exerted on an outer surface of the optical element in the region of the recess than along the groove. This makes it possible to achieve stronger fixation of the optical element at the location of the recess. Advantageously, the recess has a defined length and a defined width, so that a predefined magnitude of the compressive force at the location of the recess can be easily planned and formed. In particular, the defined length and width of the recess can be designed depending on a circumference of the optical element.

[0017] According to a further preferred embodiment, the adjustment device is designed such that the compressed air can be fed into the optics carrier between an end of the optics carrier facing the electronics card and the electronics card, or the compressed air can be fed into the optics carrier through the electronics card by means of openings provided in the electronics card.

[0018] It is further an object of the present invention to provide an adjustment method for adjusting an optical element relative to a light emitting or light receiving unit of an optoelectronic sensor, with which a precise and play-free adjustment of the optical element can be easily carried out.

[0019] The object is achieved according to the invention by a method having the features of claim 9.

[0020] The adjustment method, wherein the optical element is mounted in a cylindrical optics carrier and the light emitting or light receiving unit is arranged on an electronic card of the sensor, comprises the steps: Placing the optics carrier stationary in a defined position relative to the light emitting or light receiving unit, inserting the optical element into the optics carrier, supplying compressed air to the optics carrier in order to fix the optical element in the direction of a first and a second degree of freedom within the optics carrier transversely to a longitudinal axis of the optics carrier, regulating the supplied compressed air in order to move the optical element contactlessly in the direction of the longitudinal axis in a defined operating position and to align it with respect to the light emitting or light receiving unit, and fastening the optical element in the operating position in which the optical element is adjusted with respect to the light emitting or light receiving unit.

[0021] This results in the technical advantage that the optical element can be adjusted along the longitudinal axis of the optics carrier while simultaneously being fixed transversely to it in the direction of the other relevant degrees of freedom.

[0022] Preferably, the optical element is moved within the optics carrier along the longitudinal axis of the optics carrier toward the light emitting or light receiving unit or away from the light emitting or light receiving unit.

[0023] In particular, the optical element is secured to the optics carrier in the operating position using adhesive. Advantageously, the compressed air is turned off after the optical element has been secured. In other words, the compressed air is supplied until, for example, the adhesive has fully cured.

[0024] Furthermore, the compressed air is preferably readjusted according to any deviation in the position of the optical element from the defined operating position, if the deviation is detected during the attachment of the optical element. This allows the fixation of the optical element to be adjusted by readjusting the supplied compressed air depending on the curing of the adhesive. In addition, distortion caused by the adhesive is counteracted.

[0025] The invention will be explained in more detail below with regard to further features and advantages, using exemplary embodiments and with reference to the accompanying drawings. The figures of the drawing show: Fig. 1A is a schematic representation of a preferred embodiment of an adjustment device according to the invention with main components of an optoelectronic sensor, Fig. 1B is a schematic representation of another preferred embodiment of the adjustment device according to the invention, Fig. 2A is a three-dimensional representation of a preferred embodiment of an optics carrier with an optical element of the adjustment device according to the invention, Fig. 2B is a plan view of the preferred embodiment of the optics carrier of the Figure 2A , Fig. 3A a three-dimensional representation of a further preferred embodiment of an optics carrier with an optical element of the adjustment device according to the invention, Fig. 3B a plan view of the preferred embodiment of the optics carrier of the Figure 3A , and Fig. 3C a section of a detailed sectional view of the preferred embodiment of the optics carrier of the Figure 3A .

[0026] Figure 1A shows a schematic representation of a preferred embodiment of an adjustment device 1 according to the invention, in which a cylindrical optics carrier 2 is arranged stationary in a defined position relative to a light emitting unit 4 of an optoelectronic sensor S. The light emitting unit 4 of the sensor S is positioned next to an associated light receiving unit 5, wherein the light emitting unit 4 or light receiving unit 5 is arranged on an electronics card 6 of the sensor S.

[0027] An optical element 3, which preferably comprises an optical lens, is mounted in the cylindrical optics carrier 2, wherein the optical element 3 can be adjusted relative to the light emitting unit 4 by means of the adjustment device 1 according to the invention.

[0028] Here, the adjustment device 1 is designed such that compressed air DI—as shown by the dashed arrows—can be introduced into the optics carrier 2. The compressed air DI can be fed into the optics carrier 2, in particular, between an end of the optics carrier 2 facing the electronics card 6 and the electronics card 6, wherein the compressed air DI is guided through compressed air lines (not shown).

[0029] This enables contactless movement of the optical element 3 provided in the optics carrier 2 along a longitudinal axis L of the optics carrier 2—as indicated by the double arrow shown—because, when the optics carrier 2 is in an upright position, the optical element 3 is subjected, on the one hand, to gravity and, on the other hand, to an opposing pressure force generated by the air pressure. By adjusting and balancing these two forces, the optical element 3 can be brought into the desired operating position along the longitudinal axis L and held in place. In this operating position, in which the optical element 3 is adjusted relative to the light emitting unit 4, it can be secured, for example, by gluing.

[0030] Since the optical element 3 is not pressed into the optics carrier 2, it can still move to a certain extent in the direction of a first degree of freedom x and a second degree of freedom y within the optics carrier 2 transverse to the longitudinal axis L before it is glued. The first degree of freedom x is shown as the x-axis, which is perpendicular to the Figure 1 and points out of the page plane. The second degree of freedom y is shown as the y-axis, which runs parallel to the electronics board 6 and lies in the page plane.

[0031] The compressed air DI is now also used to hold the optical element 3 transversely to the longitudinal direction L. For this purpose, the optics carrier 2 has a plurality of grooves 8 on an inner wall 7, which extend parallel to the longitudinal axis L of the optics carrier 2 and through which the introduced compressed air DI is guided. Although a small portion of the compressed air DI will also pass through the space between the optical element 3 and the optics carrier 2, this portion should be negligible compared to the portion of the compressed air DI that flows through the grooves 8. Due to the pressure of the air in the grooves 8, lateral compressive forces F act on the optical element 3 on each open side of a groove 8.

[0032] In the first embodiment, the grooves 8 are preferably arranged at the same angular distance from each other and have the same dimensions, i.e., equally dimensioned open sides. The equally spaced arrangement of the grooves 8 to each other is evident from the Figure 2Bwhich shows a plan view of the preferred embodiment of the optics carrier 2 with the optical element 3 of the Figure 2Arepresents. A portion of the introduced compressed air DI flows through the grooves 8 on an outer side 9 of the optical element 3 along the longitudinal axis L in the direction of the z-axis. The compressed air DI flowing in the grooves 8 causes radially inwardly directed compressive forces F, which are schematically shown as black arrows. These compressive forces F hold the optical element 3 centrally in the optics carrier 2, so that the optical element 3 is fixed in the direction of the first and second degrees of freedom x and y or in the direction of the x and y axes transverse to the third degree of freedom z or the z-axis. The optical element 3 can then be moved within the optics carrier 2 along the longitudinal axis of the optics carrier 2 in the direction of the third degree of freedom z, as described above, so that the adjustment of the optical element 3 can be carried out stably and precisely without mechanical over-determination.

[0033] The introduced compressed air DI can, as described above, move the optical element 3 in the direction of a third degree of freedom, represented as the z-axis, into the operating position of the optical element 3. The operating position can preferably be determined by monitoring a change in a light spot of the light-emitting unit 4 during the contactless movement of the optical element 3, and the optical element 3 is in the operating position when the light spot of the light-emitting unit 4 is optimally adjusted. The optical element 3 is thus aligned with respect to the light-emitting unit 4 and can be attached to the optics carrier 2 in the operating position. The z-axis is coaxial with the longitudinal axis L of the optics carrier 2.

[0034] Advantageously, the compressed air DI introduced during fastening, in particular curing of an adhesive, can be regulated in such a way that any distortion caused by the curing of the adhesive is compensated, so that the optical element 3 is adjusted at all times and the light spot of the light emitting unit 4 remains optimally adjusted.

[0035] The Figure 1B shows schematically a further preferred embodiment of the adjustment device 1 according to the invention, wherein the same components as in the Figure 1A have the same reference numerals.

[0036] In this exemplary embodiment, the roles of the light transmitting unit 4 and the light receiving unit 5 are reversed, and the optics carrier 2 is now arranged stationary in the defined position relative to the light receiving unit 5. As before, the optical element 3 is held within the optics carrier 2 in the direction of the first and second degrees of freedom x and y by means of the introduced compressed air DI and can be moved contactlessly in the direction of the third degree of freedom z.

[0037] That is, the optical element 3 is movable toward or away from the light receiving unit 5, so that an optimal incidence of a received light on the light receiving unit 5 can be adjusted.

[0038] Advantageously, in this embodiment, the compressed air DI can be supplied through the electronics board 6 into the optics carrier 2 via openings 6a provided in the electronics board 6. This allows for easy control of the introduced compressed air DI.

[0039] In the Figure 2A a three-dimensional representation of a preferred embodiment of the optics carrier 2 with the optical element 3 of the adjustment device 1 according to the invention is shown, wherein the optics carrier 2 has nine grooves 8 arranged at equal angular distances from one another on the inner wall 7 of the optics carrier 2.

[0040] Figure 3A shows a three-dimensional representation of a further preferred embodiment of the optics carrier 2 with the optical element 3 of the adjustment device 1 according to the invention, wherein in comparison to the embodiment of the Figure 2Aa number of grooves 8 provided on the inner wall 7 of the optics carrier 2 is reduced.

[0041] In the exemplary embodiment, three grooves 8 are provided, arranged at equal distances from one another. Along each groove 8, at least one recess 10 is provided, which - as shown in the Figure 3C shown - has a larger cross-sectional area A1 than a cross-sectional area A2 of the groove 8. As a result, the recess 10 has a larger contact surface for the introduced compressed air DI than the groove 8, so that a greater pressure force F results.

[0042] Here, the recess 10 preferably has a defined length I and a defined width b, so that, in particular, the inwardly open side has a desired size and thus offers a defined contact surface for the compressed air DI on the optical element 3, whereby the compressive force F on the optical element 3 is adjusted to a certain extent via the geometry of the recess 10. As a result, the optical element 3 is exposed to stronger lateral compressive forces F at the position where the recess 10 is provided than in other regions of the groove 8 above or below the recess 10.

[0043] In particular, the length I and the width b of the recess 10 can be designed depending on the circumference of the optical element 3. As a result, the compressive force F on the optical element 3 can be designed as required by adapting the geometry of the recess 10.

[0044] In the Figures 2A, 2B , 3A and 3Ban arrangement of the grooves 8 is shown in which the grooves 8 are evenly distributed over the circumference, i.e. are arranged at an equal angular distance from one another on the inner wall 7 of the optics carrier 2.

[0045] According to an embodiment of the adjustment device 1 (not shown), the grooves 8 can be arranged at an unequal angular distance from one another, so that the optical element 3 experiences a non-zero resultant force transverse to the longitudinal direction and is thus not held centrally with respect to the optics carrier 2, but rather abuts laterally against a point on the inner wall 7 of the optics carrier 2. This means that the corresponding point on the inner wall 7 of the optics carrier 2 serves as a mechanical stop for the optical element 3 during its adjustment relative to the light emitting unit 4 or light receiving unit 5.

[0046] The adjustment method according to the invention for adjusting the optical element 3 to the light transmitting unit 4 or light receiving unit 5 of the optoelectronic sensor S is described below.

[0047] As already mentioned, the optical element 3 is mounted in the cylindrical optics carrier 2 and the light emitting 4 and light receiving unit 5 is arranged on the electronic board 6 of the sensor S. With the adjustment method according to the invention, the optical element 3 - as in the Figure 1A shown - relative to the light emitting unit 4 or - as in the Figure 1B shown - relative to the light receiving unit 5.

[0048] In the adjustment process, the optics carrier 2 is first fixed in a defined position relative to the light emitting unit 4 or light receiving unit 5. The optical element 3 is then inserted into the optics carrier 3.

[0049] Once the optical element 3 is inserted into the optics carrier 2, compressed air DI is introduced into the optics carrier 2. The compressed air DI can be introduced between the end of the optics carrier 2 facing the electronics card 6 and the electronics card 6, or through the electronics card 6 into the optics carrier 2 via openings 6a provided in the electronics card 6. The compressed air DI flows into a free space within the optics carrier 2, which is delimited by the optical element 3, the inner wall 7 of the optics carrier 2, and the electronics card 6.

[0050] The optical element 3 is fixed by the compressed air DI in the direction of the first and second degrees of freedom x and y within the optics carrier 2 transversely to the longitudinal axis L of the optics carrier 2.

[0051] The compressed air DI is controlled such that the optical element 3 is moved contactlessly in the direction of the longitudinal axis L into the operating position and is aligned with the light emitting unit 4 or light receiving unit 5. In particular, the optical element 3 is moved within the optics carrier 2 along the longitudinal axis L of the optics carrier 3 toward the light emitting unit 4 or light receiving unit 5 or away from the light emitting unit 4 or light receiving unit 5. In this case, monitoring is preferably carried out during the movement of the optical element 3 to ensure an optimal light spot on the light emitting unit 4 or optimal light incidence on the light receiving unit 5.

[0052] The optical element 3 is mounted in the operating position in which the light spot of the light emitting unit 4 or the light incidence on the light receiving unit 5 is optimal, so that the optical element 3 is aligned with respect to the light emitting unit 4 or the light receiving unit 5. Preferably, the optical element 3 is mounted to the optics carrier 2 in the operating position using an adhesive, in particular a UV-light self-curing adhesive. The compressed air DI is advantageously switched off after the mounting of the optical element 3 is completed.

[0053] In addition, during the curing of the adhesive, a change in the light spot of the light emitting unit 4 or the light incidence on the light receiving unit 5 is monitored and the change is counteracted by targeted control of the compressed air DI, so that distortion is prevented and the optical element 3 remains aligned with respect to the light emitting unit 4 or the light receiving unit 5 at all times. Reference symbol

[0054] 1Adjustment device 2Optical carrier 3Optical element 4Light emitting unit 5Light receiving unit 6Electronic board 6aOpenings 7Inner wall of the optical carrier 8Groove 9Outer side of the optical element 10Recess A1Cross-sectional area of ​​the recess A2Cross-sectional area of ​​the groove bWidth of the recess DICompressed air FCompression force ILength of the recess LLongitudinal axis xFirst degree of freedom ySecond degree of freedom zThird degree of freedom

Claims

1. An adjustment device (1) for adjusting an optical element (3) relative to a light transmission unit (4) or a light reception unit (5) of an optoelectronic sensor (S), wherein the optical element (3) is supported in a cylindrical optics carrier (2) and the light transmission unit (4) and / or the light reception unit (5) is / are arranged on an expansion card (6) of the sensor (S), and wherein the adjustment device (1) is configured such that the optics carrier (2) is arranged at a fixed location in a defined position relative to the light transmission unit (4) and / or the light reception unit (5); and wherein compressed air (DI) can be introduced into the optics carrier (2) to fixe the optical element (3) provided in the optics carrier (2) in the direction of a first and a second degree of freedom (x and y) within the optics carrier (2) transversely to a longitudinal axis (L) and to contactlessly move the optical element (3) in the direction of the longitudinal axis (L) into a defined operating position; wherein the optical element (3) is movable along the longitudinal axis (L) of the optics carrier (2) toward the light transmission unit (4) and / or light reception unit (5) or away from the light transmission unit (4) and / or light reception unit (5) so that the optical element (3) can be aligned in the defined operating position with respect to the light transmission unit (4) and / or light reception unit (5) and can be fastened in the operating position in which the optical element (3) is adjusted with respect to the light transmission unit (4) and / or light reception unit (5); and wherein at least two grooves (8) that extend in parallel with the longitudinal axis (L) of the optics carrier (2) and are configured to conduct the compressed air (DI) are provided at an inner wall (7) of the optics carrier (2).

2. An adjustment device (1) in accordance with claim 1, wherein the optical element (3) comprises a lens.

3. An adjustment device (1) in accordance with claim 1, wherein the grooves (8) are arranged at the same or different distances from one another on the inner wall (7).

4. An adjustment device (1) in accordance with claim 1 or claim 3, wherein at least one recess (10) that has a greater cross-sectional area (A1) than a cross-sectional area (A2) of a groove (8) is provided along the groove (8).

5. An adjustment device (1) in accordance with claim 4, wherein the recess (10) has a defined length (l) and a defined width (b).

6. An adjustment device (1) in accordance with claim 5, wherein the defined length (l) and width (b) of the recess (10) can be adapted in dependence on a periphery of the optical element (3).

7. An adjustment device (1) in accordance with any one of the preceding claims 1 to 6, wherein the adjustment device (1) is configured such that the compressed air (DI) can be supplied into the optics carrier (2) between an end of the optical carrier (2) facing the expansion card (6) and the expansion card (6) or the compressed air (DI) can be supplied into the optics carrier (2) through the expansion card (6) by means of apertures (6a) provided in the expansion card (6).

8. An adjustment method of adjusting an optical element (3) relative to a light transmission unit (4) or a light reception unit (5) of an optoelectronic sensor (S), wherein the optical element (3) is supported in a cylindrical optics carrier (2) and the light transmission unit (4) and / or the light reception unit (5) is / are arranged on an expansion card (6) of the sensor (S), said method comprising the steps: placing the optics carrier (2) in a fixed location in a defined position relative to the light transmission unit (4) and / or light reception unit (5); introducing the optical element (3) into the optics carrier (2); supplying compressed air (DI) into the optics carrier (2) to fix the optical element (3) in the direction of a first and second degree of freedom (x and y) within the optics carrier (2) transversely to a longitudinal axis (L) of the optics carrier (2); regulating the supplied compressed air (DI) to contactlessly move the optical element (3) in the direction of the longitudinal axis (L) into a defined operating position and to align it with respect to the light transmission unit (4) and / or light reception unit (5); and fastening the optical element (3) in the operating position in which the optical element (3) is adjusted with respect to the light transmission unit (4) and / or light reception unit (5), with at least two grooves (8) that extend in parallel with the longitudinal axis (L) of the optics carrier (2) and are configured to conduct the compressed air (DI) being provided at an inner wall (7) of the optical carrier (2).

9. An adjustment method in accordance with claim 8, wherein the optical element (3) is fastened to the optics carrier (2) in the operating position by means of adhesive.

10. An adjustment method in accordance with claim 8 or claim 9, wherein the compressed air (Dl) is shut down once the fastening of the optical element (3) has been completed.

11. An adjustment method in accordance with any one of the preceding claims 8 to 10, wherein the compressed air (DI) is readjusted in accordance with a deviation of the position of the optical element from the defined operating position when the deviation is detected on the fastening of the optical element (3).