Photosensor having welded connection between housing and optical module

Abstract

A photosensor, in particular a grating, is shown, comprising an elongate housing and an optical module arranged in the housing. The transmitting and / or receiving elements are arranged on the optical module at a distance from each other, and the optical module is connected to the housing via contact points, where the contact points are flat. The optical module and the housing comprise plastic. According to the invention, at least some of the contact points are designed as a welded connection, wherein the housing is welded to the optical module.

Description

Technical Field

[0001] The invention relates to a photosensor according to the preamble of claim 1 and to a method for producing a photosensor according to claim 28 . Background Art

[0002] State-of-the-art photoelectric sensors typically feature an aluminum profile within which at least one optical module is positioned. The optical module includes the components that ensure the functionality of the photoelectric sensor. In addition to the transmitting and / or receiving elements on the printed circuit board, a support body for the printed circuit board—also known as a tube—is typically part of the optical module. Depending on the design, the optical module may also include an aperture and lens assembly, which are preferably attached to the support body. The aluminum profile has one or more openings along one longitudinal side. The optical module is arranged in the profile so that the transmitting or receiving elements of the optical module are directed toward the longitudinal side with the opening. A plastic strip, transparent to the wavelength emitted by the optical module, is attached to the profile as a protective screen. The protective screen can be permanently or removably attached to the profile. However, the final connection of the two dissimilar materials creates a mechanical weakness and requires additional steps in the production of the photoelectric sensor. Furthermore, the connection must be tightly sealed to protect the optical module from splashes.

[0003] The optical module is arranged in the aluminum profile using guides running longitudinally along the profile's interior. The optical module's counter-components can be inserted into these guides, creating a form-fit and / or force-fit connection between the optical module and the aluminum profile. This type of connection requires a decision as to whether to prioritize ease of assembly or high resistance to vibration and shock. However, these two requirements are conflicting.

[0004] Instead of an aluminum profile, the profile can also be made of a different material, such as plastic. The connection to the optical module is made in the same way for a plastic profile as for an aluminum profile, and therefore the same issues exist as for an aluminum profile regarding the stability of this connection against vibrations and shock movements.

[0005] US2013 / 292554A1 discloses a grating having an optical module, which is designed to be cost-effective to manufacture and easy to install. The optical module is designed to be installed in a U-shaped profile. It has protruding elements for precisely positioning the optical module within the housing. Furthermore, the optical module may have fasteners for securing the optical module within the housing. The fasteners are preferably designed as snap-on elements. They can be securely attached to the housing. For this purpose, adhesive bonding, ultrasonic welding, or screw fastening are used.

[0006] EP 1 770 414 A1 describes an optoelectronic device having a plurality of light emitter or light receiver modules electrically connected to one another by means of a flexible printed circuit board and associated with a tube or lens body. The light emitter or light receiver modules are directly attached to their assigned tube or lens body, and a flexible light guide is directly fastened to the light emitter or light receiver module. A plastic housing is provided to accommodate the light emitter or light receiver modules, which is attached to the tube using snap-fit elements. Furthermore, the light emitter or light receiver modules can be connected to the corresponding assigned tube or lens body by means of a soldered connection. The tube can be mounted in the housing, wherein the housing has a recess for this purpose, via which the tube can be secured.

[0007] Patent EP2730952A1 discloses combining individual housing modules to construct light barriers with varying protective field heights from a uniform, short base module. A disadvantage of this variant is that each connection point involves an electrical switch that must be sealed against environmental influences. Furthermore, the mechanical stability of this connection is limited, which is why only a few housing modules can be combined. Furthermore, the maximum protective field height of a light barrier constructed in this manner is limited.

[0008] From patent US2014 / 346318, it is known that a printed circuit board equipped with spacers can be aligned with the tube pinhole aperture so that the axis of the optoelectronic component (LED / lens) precisely matches the axis of the pinhole aperture. The printed circuit board can then be fixed in place by means of a laser weld connection between the spacer element and the tube. The disadvantage of this variant is that for each beam in the grating, the optoelectronic component must be aligned with the corresponding pinhole aperture and fixed in place by laser welding. This is very time-consuming and expensive. In addition, two distance elements are required for each beam, which are required for the laser weld connection. This also leads to high manufacturing costs.

[0009] Task

[0010] The object of the present invention is therefore to propose an alternative optoelectronic sensor, in particular a light barrier, which has a simple and cost-effective way of connecting the optical module to the housing, which has increased resistance to vibrations and shocks and can be manufactured with minimal mechanical stress on the optical module and the housing. Furthermore, the sealing of the housing should be as effective as possible.

[0011] describe

[0012] This problem is solved by a photosensor having the features of claim 1 .

[0013] A photoelectric sensor, particularly a light barrier, comprises an elongated housing and an optical module disposed within the housing. Transmitting and / or receiving elements are disposed at a distance from one another on the optical module, and the optical module is connected to the housing via flat contact points. The optical module and the housing are made of plastic. At least some of the contact points are designed as welded connections, wherein the housing is welded to the optical module. The welded connection between the housing and the optical module is formed by laser transmission welding.

[0014] The housing protects the optical module of the photoelectric sensor from external influences and serves as a stabilizing element. A soldered connection provides a secure connection between the housing and the optical module inside. This has the advantage that the optical module can first be positioned by inserting it into the housing and then securely attached to the housing in a second step.

[0015] This not only simplifies the assembly process, but also creates a strong connection between the two components of the photoelectric sensor, significantly increasing its resistance to vibration and shock.

[0016] The housing can be described as an appliance housing, since it is used to house the optical module such that the optical module is completely surrounded by the housing. Thus, it is intended that the optical module is completely surrounded by the housing in the peripheral direction.

[0017] Because the components touch at the contact point, an increase in the temperature of one component causes the other to heat up as well. During this process, the temperature of the material at the irradiation point is raised to its melting point. As a result, the materials of the two components melt at the irradiated contact point, and after cooling, a permanent bond is formed. In this case, the process is called laser transmission welding.

[0018] Compared to ultrasonic welding, laser transmission welding offers the advantage of contactless energy application to the weld point. Externally irradiating the contact point with a laser beam is sufficient to create a strong weld. In contrast, in ultrasonic welding, a sonotrode, designed for this purpose, generates ultrasonic waves that come into contact with the components to be welded. Consequently, the components to be welded, i.e., the joining partners, are subjected to high joining forces during the welding process. In contrast, with laser transmission welding, the energy used to create the connection between the components, or to weld the two components, is introduced contactlessly.

[0019] The advantage of contactless connections is that no external pressure is applied to the joint. This also allows for welded contact points that do not absorb the joining force of the ultrasonic welding sonotrode or are located in closed systems. Furthermore, there is no risk of the joined parts being misaligned due to the applied joining force.

[0020] The simple design of the housing and the use of plastic for the main components of the photoelectric sensor keep manufacturing costs low. The cost of obtaining plastic is relatively low.

[0021] In a preferred embodiment, at least in the area of the contact point, either the housing is infrared-transparent and the optical module absorbs infrared radiation, or the housing absorbs infrared radiation and the optical module is infrared-transparent. The contact point occurs at the contact point or contact surface between the housing and the optical module. If one of the two components absorbs infrared radiation in the area of the contact point, irradiating the contact point with the infrared laser beam will result in a localized temperature increase. During the manufacturing process, this can be so severe that the plastic material melts at the irradiation point.

[0022] Advantageously, the contact points of the optical module and the housing each comprise mutually compatible plastics, particularly thermoplastics, and even more preferably polycarbonate. In the context of the present invention, "compatible" means that the plastics can be joined together by laser welding. By melting the plastic materials of the two components, a particularly resistant weld connection can be created. If the same plastic material is used, the optical module and the housing will experience the same thermal expansion during the welding process and also during subsequent operation due to the same thermal expansion coefficient, preventing stress in the weld points due to thermal expansion.

[0023] In another preferred embodiment, the plastic material of at least one of the two components is mixed with an infrared-absorbing additive at the intended contact point between the optical module and the housing. The infrared-absorbing material is evenly distributed throughout the plastic. Mixing the plastic with such an additive eliminates the need for additional steps after the components have been manufactured, as the additive is already integrated into the plastic at the contact point.

[0024] In another preferred embodiment, the optical module includes a support body on which a printed circuit board with transmitting and receiving elements is arranged. The transmitting and receiving elements are thus arranged on the printed circuit board, wherein the support body, as a component of the optical module, has, among other things, the task of holding the printed circuit board. The printed circuit board can be connected to the support body with a form-fitting or force-fitting connection. It is also conceivable that the printed circuit board be arranged on several supports.

[0025] The support body and housing are advantageously made of compatible thermoplastics. Thus, a welded connection can be formed between the housing and the support body. In this design, the support body is part of the optical module and is made of a thermoplastic material compatible with the housing. The welded connection between the housing and the support body allows for a modular optical module design. Other components that may be included as part of the optical module can have other functions and do not necessarily need to be made of a compatible plastic.

[0026] Such further assemblies may in particular comprise a lens assembly or an aperture assembly. Preferably, the lens and / or aperture assembly is provided on a support body opposite the transmitting or receiving element. The lens assembly in particular comprises a lens whose function is to disperse or concentrate the incident or outgoing beam. The aperture assembly serves to limit the amount of light emitted by the transmitting element or received by the receiving element. The aperture assembly ensures the resolution of the safety light barrier. The resolution of the safety light barrier determines the size of the minimum detectable object. Since the optical module may comprise an aperture and a lens assembly, the welded connection between the optical module and the housing may also be performed via the aperture and / or lens assembly.

[0027] It is conceivable that the two supports that are in contact at the front are connected via a lens or aperture assembly.For example, the aperture assembly can have a positioning lug on the side facing the support, and this positioning lug can be vertically inserted into the recess provided on the two supports.

[0028] Preferably, at least the support body and the housing are made of polycarbonate. Polycarbonate has a higher impact strength than alternative plastics such as PMMA.

[0029] It is useful for the transmitting element to comprise a light emitting diode and the receiving element to comprise a photodiode. Light emitting diodes and photodiodes are widely available.

[0030] The housing is preferably cylindrical, in particular cylindrical. The surface of the cylindrical housing end is annular, and the inner wall of the cylindrical housing is formed by the cylindrical surface, thus allowing an interference fit to close the opening of the cylindrical housing end.

[0031] The housing preferably has a closed cross-section. This means that the housing has no joints or transitions between the two components or semi-finished products in the circumferential direction. Alternatively, the transverse surfaces of the housing can be said to be integral. This eliminates the need for sealing elements and increases the stability of the housing.

[0032] The design of a housing with a closed cross-section, combined with creating a connection between the housing and the optical module by laser transmission welding, allows for the controlled introduction of heat to form the welded connection. Laser transmission welding makes it possible to weld the optical module to the housing using a housing that is closed on all sides. Using another welding method, such as ultrasonic welding, would require an open housing (U-shaped profile). This is because in ultrasonic welding, energy is transferred via vibrations, and the components to be welded must be securely clamped. Since the optical module cannot be clamped in a closed housing, it will vibrate during ultrasonic welding. This, in turn, precludes the controlled introduction of heat to form the welded connection between the housing and the optical module. For this reason, forming a welded connection between the housing and the optical module by laser transmission welding cannot be simply replaced by ultrasonic welding. Furthermore, the closed housing eliminates the need for additional connection points between the two housing components, which would otherwise have to be connected and sealed in some other way.

[0033] In another preferred embodiment, the housing comprises an elongated base body that forms a housing for the optical module and has at least one opening on a longitudinal side and a protective screen that closes the opening. This is an alternative design to the cylindrical housing described above. The optical module can be inserted through the longitudinal side opening or through the longitudinal end opening. The connection between the elongated base body and the protective screen can be either fixed, i.e., inseparable, or removable. The protective screen is designed to allow electromagnetic radiation from the transmitting and receiving elements of the photosensor to pass through.

[0034] The base is preferably a U-shaped profile with an opening on one longitudinal side. The U-shaped profile is characterized by a stable form combined with low material costs and high capacity. This makes it a good choice for the housing base. Furthermore, the U-shaped profile simplifies assembly of the optical module because it is open on one longitudinal side.

[0035] The protective screen is advantageously welded to the base body at the edges, preferably by laser transmission welding. This welded connection creates a strong bond between the base body and the protective screen and preferably forms a waterproof seal between these components at the edges of the protective screen to meet IPX5, IPX7, and IPX9K protection ratings. Furthermore, laser transmission welding can help increase production speeds while simultaneously reducing manufacturing costs, for example by eliminating the need for additional sealing elements such as O-rings, adhesives, tape, and the like.

[0036] In another preferred embodiment, end caps are attached to the two open longitudinal ends of the housing. The end caps are used to close the openings at the longitudinal ends.

[0037] The end cap is advantageously made at least partially of an infrared-absorbing plastic. Therefore, the end cap can also be connected to the housing or optical module by means of laser transmission welding. This makes the interior of the housing splash-proof. The end cap is preferably securely attached to the housing and / or optical module. The material-locked connection creates a robust connection between the end cap and the housing or optical module. The material bond between the end cap and the housing and / or optical module is preferably produced by laser transmission welding. The end cap is advantageously attached to the housing or optical module by means of laser transmission welding. For laser transmission welding between the end cap and the housing or optical module, the end cap, the housing, or the optical module must absorb infrared radiation at least at the contact surfaces.

[0038] Another advantage is that the laser welding method can also be used to form welded connections around the entire perimeter of the housing, including on the front side. Lengths of almost two meters are common for light barriers. With such dimensions, measuring the joining force of ultrasonically welded connections on components would be impossible, or only possible with considerable effort.

[0039] The end cap closes two openings in the sensor housing that face each other. Preferably, the connection between the end cap and the housing—in particular, a weld—forms a seal. It is conceivable for the end cap to have an annular shoulder that projects into the interior of the housing and whose outer diameter corresponds to the inner diameter of the housing. This allows the end cap to be connected to the housing over its entire circumference, creating a welded connection that ensures protection against splash water. This type of connection has the advantage of not requiring an additional seal between the housing and the end cap. Therefore, the proposed welded connection prevents moisture penetration, particularly if the photoelectric sensor is exposed to varying temperatures during use. This type of connection is also suitable for higher water ingress protection classes, such as IP69K.

[0040] In another preferred embodiment, two or more optical modules can be coupled to each other at the front. This has the advantage of enabling the production of sensor assemblies with different protection field heights. Thus, the sensor housing can be several times the length of a single optical module.

[0041] Preferably, the transmitting and / or receiving elements of all optical modules in the housing point in the same radial direction of the cylindrical housing. For the light barrier, it is important that all beams of the photosensors are completely parallel to ensure that the light barrier can be aligned as well as possible.

[0042] In another preferred embodiment, the optical modules have a first plug-in connection at one longitudinal end and a second plug-in connection at the opposite longitudinal end, wherein the first and second plug-in connections can be coupled to each other. It is important that the plug-in connection between the two optical modules ensures precise mutual alignment with minimal play and that the optical modules cannot be twisted about their longitudinal axes, so that the beam axes of the optical modules are aligned parallel.

[0043] Preferably, the first plug-in connection is designed as a plug (male) and the second plug-in connection is designed as a socket (female).A plug and socket connection is a reliable and cost-effective way of coupling two or more optical modules.

[0044] The end caps preferably have plug-in connections that can be coupled to the plug-in connections of the end optical modules. This prevents relative rotation between the optical modules and adjacent end caps about the longitudinal axis of the housing. Due to the coupling of the end caps to the optical modules, alignment of the optical modules can be achieved by rotating the coupled end caps prior to welding. The end caps may, for example, have positioning markings that define the welding position of the optical modules in the machine holder or allow a specialist to easily determine the correct welding position of the optical modules optically.

[0045] In another preferred embodiment, the photosensor comprises a mounting assembly for fastening the photosensor to a substrate.The mounting assembly is advantageously connected to the housing of the photosensor by laser transmission welding, which in turn results in low production costs.

[0046] Another aspect of the present invention relates to a photosensor, particularly a light barrier, having an elongated housing and at least two optical modules arranged therein. The photosensor is characterized in that the optical modules can be coupled to each other at the front end by means of a plug-in connection, with the optical modules having a plug at a first longitudinal end and a socket at a second end. The plugs and sockets of the optical modules are shaped and positioned so that the plug of the first optical module can be inserted into the socket of the second optical module, thereby preventing relative rotation of the optical modules about the longitudinal axis. This type of plug-in connection between the two optical modules ensures that the modules are always aligned identically after coupling.

[0047] Another aspect of the present invention relates to a method for manufacturing a photoelectric sensor, which includes an elongated housing and an optical module, wherein the optical module is inserted into the housing, aligned in the housing, and then joined to the housing by laser transmission welding. Transmitting and / or receiving elements are arranged on the optical module, and the photoelectric sensor is preferably used to form a light barrier. Ideally, the elongated housing has an opening at at least one longitudinal end through which the optical module can be inserted into the housing. The optical module is aligned in the housing so that the transmitting and / or receiving elements on the optical module point in the desired direction. In order to use laser transmission welding, the optical module must be in contact with the housing. The contact point between the housing and the optical module serves as the welding point.

[0048] The housing has an opening at at least one longitudinal end. The optical module is preferably inserted through the open longitudinal end of the housing. By using the open longitudinal end, there is no need for an additional opening in the housing, which ensures greater dimensional stability of the housing.

[0049] The opening at the longitudinal end of the housing forms the smallest possible surface and can be closed relatively easily due to its position at the end of the housing. Preferably, the opening at the longitudinal end of the housing is closed with an end cap after the optical module has been inserted into the housing.

[0050] The end cap should seal the housing to protect the optical module inside from the external environment. The end cap can be welded to the housing or optical module, preferably using laser transmission welding. The welded connection between the end cap and the housing creates a seal, eliminating the need for a separate sealing component. This allows the end cap to be attached to the housing or optical module in the same manner as the optical module is already attached to the housing, thereby simplifying the production process and reducing costs.

[0051] After inserting the optical module into the housing, it is important to ensure that the optical module is centered within the housing. This can be accomplished by using a support arm on the optical module. The optical module preferably has a support arm that, when inserted into the housing, contacts the housing and centers the optical module within the housing. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] The invention is described in more detail below with reference to the accompanying schematic drawings. The preferred features mentioned can be implemented in any combination - as long as they are not mutually exclusive. It is shown in a non-scale schematic representation:

[0053] Figure 1 : A three-dimensional partial view of a first photoelectric sensor according to the present invention, comprising a housing and an optical module arranged therein;

[0054] Figure 2 :pass Figure 1 Longitudinal cross section of the photoelectric sensor;

[0055] Figure 3 : A perspective view of the first photoelectric sensor, wherein the opposite openings of the housing are closed with end caps;

[0056] Figure 4 : A front view of the first photosensor with the end cap removed;

[0057] Figure 5 : A perspective view of several optical modules arranged in a row;

[0058] Figure 6 : Perspective view of a second photosensor with a two-part housing. DETAILED DESCRIPTION

[0059] In the following, the same reference symbols denote the same or functionally identical elements (in different figures). In other embodiments, additional primes may be used to distinguish similar or functionally equivalent or functionally similar elements.

[0060] Figure 1 A photosensor 11 according to the present invention is shown. Photosensor 11 comprises a housing 13 and an optical module 15, on which a printed circuit board 19 with a light source or light sensor is arranged. In the example shown, housing 13 is transparent and formed from a hollow cylinder. The length of cylindrical housing 13 is many times greater than its diameter. Optical module 15 is placed inside housing 13. Optical module 15 comprises a support body 17, a lens assembly 21, a printed circuit board 19, and an aperture assembly 22 (the lens assembly is not visible in this view). Lens assembly 21 and aperture assembly 22 are arranged on the same longitudinal side of the support body, while printed circuit board 19 is arranged on the opposite longitudinal side of support body 17. In the illustrated design, printed circuit board 19 and aperture assembly 21 do not contact housing 13. It is conceivable that the connection between optical module 15 and housing 13 is established by lens assembly 21, aperture assembly 22, or components specifically incorporated for this purpose.

[0061] The support 17 has protrusions 26 on its longitudinal sides 25, which extend as far as the housing 13 and create contact points therewith. In the embodiment shown, the support 17 has three contact points 24 on each longitudinal side. These contact points 24 serve as welding points for connecting the support 17 to the housing 13.

[0062] Support arms 23 are attached at regular or irregular intervals along the length of optical module 15. Support arms 23 are used to position optical module 15 within housing 13. Support arms 23 extend vertically from respective longitudinal sides 25 so that they contact housing 13. Although not provided in the illustrated design, support arms 23 can also serve as welding points. Other functions of support arms 23 are described below.

[0063] Figure 2 Shown Figure 1A longitudinal cross-section of a partial area of a photosensor is shown in FIG. A hollow cylindrical housing 13 forms the outer boundary of the sensor 11. An optical module 15 is arranged therein, comprising, among other things, a support body 17. A printed circuit board 19 is arranged along one side of the support body 17, on which the transmitting or receiving element 29 of the photosensor 11 is mounted. The beams from the transmitting and receiving elements 29 must pass through the support body 17. To this end, a continuous recess 31 is provided in the support body 17 at the level of the transmitting or receiving element. The lens assembly 21 is arranged at the end of the recess 31 opposite the transmitting or receiving element 29. The lens assembly 21 is attached to the support body 17 by means of an aperture assembly 22, which serves as the aperture of the lens assembly 21 and ensures the desired resolution of the optical grating. The aperture assembly 22 has a plate-like structure with a positioning lug 28 protruding vertically from one flat side. The support body 17 has a recess to accommodate the positioning lug 28 of the aperture assembly 22. The positioning lugs 28 and the recess in the support 17 are dimensioned in such a way that a friction connection is created between the support 17 and the aperture assembly 22 when the positioning lugs 28 are inserted into the recess. The length of the aperture assembly 22 may differ from the length of the support 17. It is possible that several aperture assemblies 22 are arranged on one support 17.

[0064] The hollow cylindrical housing 13 has an opening 32 at each of its longitudinal ends. These openings can each be closed with an end cap 27. Figure 2 In the example, an opening 32 of a hollow cylindrical housing 13 is closed by an end cap 27. A first region 33 of the end cap 27 extends through the opening into the hollow cylinder, contacting the inner side of the housing wall. A second region 34 of the end cap 27, located outside the housing 13, is attached to the longitudinal end of the housing, creating an annular contact surface between the end cap 27 and the housing 13. The contact surface in the first region 33 can serve as a welding point. The cylindrical surface serving as the contact surface between the end cap 27 and the housing 13 in the first region 33 enables laser welding using a laser beam oriented perpendicular to the housing 13. On the other hand, the contact surface in the second region 34 requires laser welding using a laser beam oriented at an acute angle to the housing wall. By rotating the laser beam source or the housing 13 about its central axis, a continuous welded connection can be created between the housing 13 and the end cap 27 in a single step.

[0065] Figure 3The photoelectric sensor 11 is shown in its entirety. The housing 13 of the photoelectric sensor is cylindrical. The optical module is arranged inside the housing 13 and is not shown in this figure. End caps 27 are attached to the two ends of the cylindrical housing 13. One end cap 27' has an opening for a connector 35. The connector 35 forms an interface with another electrical device, so that information from the photoelectric sensor 11 can be transmitted via the connector 35 to, for example, a control unit attached to it. At the same time, information from the optical module 15 adjacent to the end cap 27 is transmitted to the connector 35 via its printed circuit board 19. The end cap 27 completely covers the surface at the end of the cylindrical housing 13. The part of the end cap 27 that protrudes above the housing 13 is designed as an octagonal nut. Among other things, this allows for a better view of the position of the end cap and the optical module and prevents the grating from rolling away.

[0066] Figure 4 1 is a front view of the photoelectric sensor 11, showing the connector 35 but not the end caps. The optical module 15 is placed inside the cylindrical housing 13. The optical module 15 contacts the housing 13 via the protrusions 26 on the longitudinal side 25 and via the support arms 23. Figure 4 In the cross-section shown in FIG, there are four points of contact between the optical module 15 and the housing 13. In the illustrated design, only the optical module's protrusions 26 are intended to be welded. Support arms 23 are used to position the optical module 15 within the housing 13 until a welded connection is established. The distance between the opposing protrusions 26 is slightly greater than the inner diameter of the housing 13, creating an interference fit between the optical module 15 and the housing 13. Support arms 23 are approximately perpendicular to the plane formed by the opposing protrusions 26 and, through contact with the housing, induce a force in the opposite direction. (?) Even though this force is very small, it helps secure the optical module 15 in the housing 13 until a welded connection is established.

[0067] One or several printed circuit boards 19 are held in a form-fitting manner in the optical module 15. When more than one printed circuit board 19 is used, the electrical connections between adjacent printed circuit boards 19 are made via connecting plugs 37. These are intended to be attached to the printed circuit boards 19.

[0068] Optical module 15 has a plug 39 at one end and a socket at the other, which together form a plug-and-socket connection. This means the size and position of the plug and socket are chosen so that plug 39 of optical module 15 can be plugged into the socket of another optical module. The socket is arranged at the same height and width as plug 39. This connection prevents any twisting of the optical modules relative to each other and ensures that after two optical modules 15 are connected, the transmitters or receivers of all 15 optical modules are aligned in the same direction.

[0069] Figure 5Two interconnected optical modules 15 and 15' are shown. In the embodiment shown here, a printed circuit board 19 is arranged on one longitudinal side of the support bodies 17 and 17', while a lens assembly 21 is arranged on the opposite longitudinal side of the support bodies 17 and 17'. An aperture assembly 22 is mounted on the side of the optical module 15 on which the lens assembly 21 is arranged. The aperture assembly 22 is designed to be attached to the optical module 15 in such a way that a continuous aperture assembly 22 is arranged at the transition between the two optical modules 15. Therefore, the aperture assembly 22 arranged on both optical modules 15 and 15' ensures that the resolution is consistent across the modules. During assembly, the optical modules 15 are first joined together via their plug and socket connections, allowing the transmitters or receivers of the optical modules 15 to be immediately aligned. To this end, the plug 39 of the initial optical module 15 is inserted into the socket of the second optical module. In a second step, the aperture assembly 22 is attached to the optical modules, connecting the adjacent optical modules 15 to form a chain of optical modules. Adjacent printed circuit boards 19 are connected to each other via connecting plugs 37. The connecting plugs form an electronic connection between the two printed circuit boards 19. Figure 5 As an alternative to the embodiment shown in , it is also conceivable that the aperture assembly is not arranged on both supports, but rather a new aperture assembly is arranged at the transition from one support to the adjacent support.

[0070] Figure 6 Another embodiment of a photosensor according to the present invention is shown. Compared to the previously shown designs, housing 13 has a rectangular cross-section rather than a circular one. Housing 13 is formed from a U-shaped profile 45 and a protective screen 47, which is arranged on U-shaped profile 45 so that it closes the U-shaped profile opening. An optical module is placed in housing 13. Optical module 15 can be attached to both the U-shaped profile 45 and the protective screen 47 of the housing.

[0071] End caps 27 are also provided to close the openings at both ends of the housing 13 shown here. The end caps 27 have a shape corresponding to the cross section of the U-shaped profile 45 and can be arranged adjacent to the corresponding openings of the U-shaped profile 45.

[0072] Although specific embodiments have been described above, it will be apparent that different combinations of the shown embodiments may be used, as long as these embodiments are not mutually exclusive.

[0073] List of reference numerals:

[0074] 11 Photoelectric sensor

[0075] 13 Housing

[0076] 15 Optical Module

[0077] 17 Support

[0078] 19 printed circuit boards

[0079] 21 Lens assembly

[0080] 22 Aperture assembly

[0081] 23 Support Arm

[0082] 24 touchpoints

[0083] 25 longitudinal side

[0084] 26 protrusion

[0085] 27 End cap

[0086] 28 Positioning lugs

[0087] 29 Transmitting or receiving element

[0088] 31 Continuous depressions on the support

[0089] 32 Opening at the longitudinal end of the housing

[0090] 33 Contact surface in the first area

[0091] 34 Contact surface in the second area

[0092] 35 connector

[0093] 37 PCB connection plug

[0094] 39 plug

[0095] 45 U-shaped profile

[0096] 47 Protective screen

Claims

1. A photoelectric sensor (11), in particular a grating, comprising - an elongated housing (13) and - an optical module (15) arranged in the housing (13), wherein - the transmitting and / or receiving elements (29) are arranged at a distance from one another on the optical module (15), - the optical module (15) is connected to the housing (13) via contact points (24), and - the optical module (15) and the housing (13) comprise plastic, It is characterized by At least some of the contact points (24) between the optical module (15) and the housing (13) are designed as welded connections, and the welded connection between the housing (13) and the optical module (15) is formed by laser transmission welding.

2. The photoelectric sensor (11) according to claim 1, characterized in that At least in the region of the contact points (24) designed as soldered connections, either the housing (13) is transparent to infrared radiation and the optical module (15) absorbs infrared radiation, or the housing (13) absorbs infrared radiation and the optical module (15) is transparent to infrared radiation.

3. The photoelectric sensor (11) according to one of claims 1 to 3, characterized in that The contact points (24) of the optical module (15) and the housing (13) each comprise mutually compatible plastics, in particular thermoplastics, more preferably polycarbonate.

4. The photoelectric sensor (11) according to one of claims 1 to 4, characterized in that At the intended contact point (24) of the optical module (15) with the housing (13), an infrared absorbing additive is added to the plastic material of at least one of the two components.

5. The photoelectric sensor (11) according to one of claims 1 to 5, characterized in that The optical module (15) comprises a support body (17) on which a printed circuit board (19) with transmitting or receiving elements is arranged.

6. The photoelectric sensor (11) according to claim 6, characterized in that The support body (17) and the housing (13) are made of compatible thermoplastic materials, and a welded connection is made between the housing and the support body (17).

7. The photoelectric sensor (11) according to claim 6 or 7, characterized in that The lens (21) and / or aperture assembly (22) is provided on the support (17) opposite the transmitting or receiving element (29).

8. Photoelectric sensor (11) according to one of claims 6 to 8, characterized in that At least the support body (17) and the housing (13) are made of polycarbonate.

9. The photoelectric sensor (11) according to one of claims 1 to 9, characterized in that The transmitting elements each include a light emitting diode, and the receiving elements each include a photodiode.

10. The photoelectric sensor (11) according to one of claims 1 to 10, characterized in that The housing (13) has a cylindrical shape, preferably a circular cylindrical shape.

11. The photoelectric sensor (11) according to one of claims 1 to 11, characterized in that The side surfaces of the housing (13) are integral.

12. Photoelectric sensor (11) according to one of claims 1 to 11, characterized in that The housing (13) comprises an elongated base body which forms a receiving space for the optical module and has at least one opening on a longitudinal side and a protective screen (47) which closes at least the opening.

13. The photoelectric sensor (11) according to claim 13, characterized in that The base body is a U-shaped profile (45) provided with one or more openings on one longitudinal side.

14. The photoelectric sensor (11) according to claim 13 or 14, characterized in that The protective screen (47) is welded to the base body at the edges, preferably by laser transmission welding.

15. Photoelectric sensor (11) according to one of claims 13 to 15, characterized in that The welded connection between the base body and the protective screen (47) forms a connection that is splash-tight against water.

16. Photoelectric sensor (11) according to one of claims 1 to 16, characterized in that End caps (27) are attached to the two open longitudinal ends of the housing (13).

17. The photoelectric sensor (11) according to claim 17, characterized in that The end cap (27) is at least partially made of infrared absorbing plastic.

18. The photoelectric sensor (11) according to claim 17 or 18, characterized in that The end cap (27) is securely attached to the housing (13) and / or the optical module (15).

19. The photoelectric sensor (11) according to one of claims 17 to 19, characterized in that The end cap (27) is attached to the housing (13) and / or the optical module (15) by means of laser transmission welding.

20. The photoelectric sensor (11) according to one of claims 17 to 20, characterized in that The connection between the end cap (27) and the housing (13), in particular a weld, forms a seal.

21. The photoelectric sensor (11) according to one of claims 1 to 21, characterized in that Two or more optical modules (15) can be connected to each other on the front side.

22. The photoelectric sensor (11) according to one of claims 1 to 22, characterized in that The transmitting and / or receiving elements (29) of all optical modules (15) in the housing (13) are directed in the same radial direction of the cylindrical housing.

23. The photoelectric sensor (11) according to one of claims 1 to 23, characterized in that The optical module (15) has a first plug-in connection at one of its longitudinal ends and a second plug-in connection at its opposite longitudinal end, it being possible for the first and second plug-in connections to be coupled to each other.

24. The photoelectric sensor (11) according to claim 24, characterized in that The first plug-in connection is designed as a plug (39) and the second plug-in connection is designed as a socket.

25. The photoelectric sensor (11) according to claim 24 or 25, characterized in that The end cap (27) has a plug-in connection that can be coupled to a plug-in connection of the terminal optical module (15).

26. Photoelectric sensor (11) according to one of claims 1 to 26, characterized in that The photoelectric sensor (11) includes a mounting assembly for fastening the photoelectric sensor (11).

27. A method for producing a photoelectric sensor (11), said photoelectric sensor (11) comprising an elongated housing (13) and an optical module (15) arranged in said housing, - a transmitting and / or receiving element (29) arranged on the optical module (15), - the optical module (15) is inserted into the housing (13), and - aligned in it, It is characterized by The optical module (15) is connected to the housing (13) by laser transmission welding.

28. The method according to claim 28, characterized in that The optical module is inserted through the open longitudinal end of the housing.

29. The method according to claim 29, characterized in that After the optical module has been inserted, the open longitudinal ends are closed with end caps.

30. The method according to claim 30, characterized in that The end cap is welded to the housing or the optical module, preferably by means of laser transmission welding.

31. The method according to claim 28, wherein The optical module includes a support arm that, when inserted into the housing, contacts the housing and centers the optical module in the housing.

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