OPTICAL SENSOR

Description

[0001] The invention relates to an optical sensor.

[0002] Such optical sensors are generally used to detect objects in a surveillance area.

[0003] In the simplest embodiment, the optical sensor comprises only a transmitter that emits light beams and a receiver that receives light beams. The optical sensor can be designed as a light sensor, distance sensor, reflective light barrier, and the like, with the transmitter and receiver being integrated into a common housing in these embodiments. Furthermore, the optical sensor can also be designed as a light barrier. In this case, the transmitter and receiver are housed in separate housings.

[0004] In general, the optical sensor can also have multiple transmitters and / or receivers. An example of such an optical sensor is a light curtain.

[0005] The light curtain typically comprises a series arrangement of light beam emitting transmitters in a first housing at one edge of the monitoring area and a series arrangement of light beam receiving receivers in a second housing at the opposite edge of the monitoring area.

[0006] The optical sensor has an evaluation unit as an electronic component, in which an object detection signal is generated depending on the received signals from the receiver(s). This object detection signal can be embodied, in particular, as a binary switching signal, whose switching states indicate whether or not an object is present in the monitoring area. Alternatively, the object detection signal can be an analog signal, for example, a distance value.

[0007] The sensor components and the electronic components of the optical sensor are arranged on at least one printed circuit board. The or each printed circuit board is housed in the or in a housing of the optical sensor.

[0008] Each circuit board must be stored precisely in a specific target position. This target position must be maintained even under external environmental influences such as vibration or pivoting loads. To achieve this, the circuit boards are secured in the respective housings using fasteners. One example of this is screw connections.

[0009] These fastenings require the use of tools and are also time-consuming.

[0010] DE 102 15 536 A1 relates to a housing, in particular a sensor housing, with at least one wall element suitable for accommodating printed circuit boards. The housing comprises at least one coupling region formed on the wall element, in which a printed circuit board can be connected to the wall element at approximately 90° to the plane of the wall element, and electrical conduction elements fixed to the wall element, which electrically connect sections of the coupling regions to one another and / or to other components. The coupling regions are designed such that, when connected to the wall element, the printed circuit board is both fixed to the wall element and can be brought into electrically conductive contact with the conduction elements.

[0011] EP 2 660 629 A1 relates to an optical module for a light curtain. The optical module comprises a circuit board. The circuit board is held in housing receptacles by means of spring elements.

[0012] DE 85 12 541 U1 relates to a device for holding electrical or electronic components, such as light-emitting diodes, on a circuit board of a device. One or more light-emitting diodes can be plugged into a connector connected to a cable. The connector can be secured in a housing by means of spring hooks, and the housing can be clamped to a circuit board by means of additional spring hooks.

[0013] DE 10 2016 121 913 A1 relates to a multi-beam light barrier with two housings, each containing transmitter modules and receiver modules. Each module has a circuit board attached to a tube with snap-in hooks.

[0014] US 2010 / 0328947 A1 relates to a light-emitting diode array comprising an array of light-emitting diodes on a printed circuit board. The printed circuit board is flexible, allowing it to be bent to fit the mounting surface of a holder and inserted with its edges into recesses in the holder.

[0015] The invention is based on the object of providing an optical sensor of the type mentioned above which can be mounted efficiently and cost-effectively.

[0016] To achieve this object, the features of claim 1 are provided. Advantageous embodiments and expedient developments of the invention are described in the dependent claims.

[0017] The invention relates to an optical sensor for detecting objects within a monitored area, comprising sensor components and electronic components arranged in at least one housing in which at least one printed circuit board accommodating sensor components and / or electronic components is mounted. The printed circuit board is mounted in a receptacle of the housing without play in that elements on the printed circuit board are deformed when the printed circuit board is inserted into a desired position in the receptacle. The elements on the printed circuit board are deformable in the receptacle such that they are mounted in the receptacle without play.

[0018] The optical sensor according to the invention can generally comprise only one transmitter and one receiver as sensor components, in which case the optical sensor can be designed as a light barrier, reflective light barrier, light scanner, distance sensor, or the like. The optical sensor can also comprise a multiple arrangement of transmitters and / or receivers. In particular, the optical sensor can be designed as a light curtain.

[0019] The functionality of the optical sensor is generally such that the optical sensor has an evaluation unit as an electronic component in which, depending on the received signals from the receiver(s), an object detection signal is generated which indicates whether an object is present in the monitoring area.

[0020] The optical sensor can generally be designed as a safety sensor. For use in safety technology, it has a fail-safe design, which is achieved, for example, by a two-channel evaluation unit.

[0021] According to the invention, the or each printed circuit board is mounted in an associated receptacle of the housing without play, in that either the printed circuit board or the elements arranged thereon are deformable at least in sections. When the printed circuit board is inserted into a desired position in the associated receptacle, it is mounted in the receptacle without play by the deformable sections.

[0022] The circuit board is thus reproducibly and stably mounted in the desired position. The deformable sections ensure that the circuit board is securely held in the holder, even when exposed to external influences such as vibration, impact, or shock loads.

[0023] This is particularly important for optical sensors designed as safety sensors, as they must meet strict requirements regarding insensitivity to such loads.

[0024] Another key advantage of the invention is that the circuit board can be secured in the respective mounts without the need for tools. This enables simple and quick installation of the optical sensor.

[0025] According to a first variant of the invention, the circuit board forms a resilient joint in an edge region, which can be deflected by deformation and which can be brought into engagement with the receptacle.

[0026] The spring-loaded joint is a component of the circuit board and can therefore be efficiently manufactured during the circuit board manufacturing process.

[0027] The functionality is such that when the circuit board is inserted into the respective receptacle, the spring-loaded joint is deflected, whereby the spring-loaded joint is clamped, locked or similarly connected to the receptacle, whereby the circuit board is positioned precisely and without play in the receptacle without any further work processes, aids or fastening means.

[0028] According to a first advantageous embodiment, the resilient joint is a film joint formed integrally with a flat body part of the printed circuit board and separated from it by a recess.

[0029] The function is such that, in a resting position, the film joint protrudes laterally beyond the edge of the body part. When a circuit board is inserted into a groove forming the receptacle, the film joint is pressed between the body part and the groove, ensuring that the circuit board is seated in the receptacle without play.

[0030] In the simplest case, the interfaces of the film joint run parallel to the edge surfaces of the body part. To achieve this, when the circuit board is inserted into the holder, the film joint is deflected in the plane of the circuit board, thereby compressing the circuit board into the holder.

[0031] Alternatively, the film joint can have chamfers, so that the side of the film joint facing the body part of the circuit board and / or the receptacle is beveled. This causes the film joint to be deflected out of the plane of the body part when pressed into the receptacle, thereby achieving particularly effective pressing of the circuit board in the receptacle.

[0032] In these embodiments, the receptacle expediently has two grooves arranged in the housing that run parallel to one another and in which opposite edges of the circuit board are mounted.

[0033] To ensure that the circuit board is securely pressed into the grooves, it is sufficient if there is a film hinge on one of the sides of the circuit board.

[0034] According to a further variant of the invention, the housing comprises a housing base body and a housing cap that can be placed over an opening in the housing base body. Opposite edge regions of the circuit board can be mounted in grooves in the housing base body, which are components of the receptacle.

[0035] In this case, the housing is constructed in two parts. The circuit board is then first inserted into the grooves of the housing base body. The circuit board can be mounted with play in the grooves as elements of the receptacle, at least until the housing cap is fixed onto the opening of the housing base body. The position is then fixed by means of the housing cap, which either has an integrated receptacle or secures the position, in particular by clamping the circuit boards in the grooves.

[0036] According to a first embodiment, the spring-loaded joint of the printed circuit board is mounted without play on an inner wall of the housing cap.

[0037] The spring-loaded joint is conveniently mounted on the inner wall of the housing cap by means of a form-locking element, ensuring no play.

[0038] The inner wall of the housing cap and the form-locking element thus form a mount for the play-free mounting of the circuit board.

[0039] Depending on the design of the form-locking element, the spring-loaded joint is deflected out of the plane of the circuit board by the form-locking element.

[0040] According to a further embodiment, a front section of the circuit board is mounted in the housing cap by means of the resilient joint such that the circuit board is arranged at an angle to the longitudinal axis of the housing cap. After inserting the circuit board into the grooves of the housing base, the resilient joint is bent, whereby the edge areas of the circuit board are mounted in the grooves under tension.

[0041] In this case, the circuit board is first pushed into the grooves of the housing base body, initially sitting in the grooves with some play. Since the circuit board is mounted at an angle in the housing cap, the housing cap is then oriented at a corresponding angle to the housing base body. To attach the housing cap to the housing base body, the housing cap must be aligned with the housing base body, which deflects the spring-loaded joint. This leads to a tilt of the circuit board in the grooves and thus to the circuit board jamming in the grooves, whereby the circuit board is mounted in its desired position with no play. The circuit board is then secured in this position by the housing cap.

[0042] The spring-loaded joint is advantageously a separate element connected to the front edge of the circuit board.

[0043] Alternatively, the fact that the circuit board itself is flexible can be exploited. Thus, the circuit board itself can form the spring-loaded joint.

[0044] According to a further embodiment, the printed circuit board has a region with widened edge regions, wherein these edge regions have different heights.

[0045] The edge areas are conveniently arranged opposite each other on the circuit board.

[0046] The height profiles of the prepared edges of the circuit board are dimensioned so that when the edges of the circuit board are inserted at an angle into the grooves, they are guided with some clearance. By aligning the circuit board in the plane of the grooves, the edges of the circuit board are clamped firmly in the grooves. The circuit board is fixed in this position by the housing cap.

[0047] According to a first embodiment, local elevations in the edge areas of the circuit board are components of the circuit board.

[0048] Alternatively, local elevations in the edge areas of the circuit board can be formed by additional elements.

[0049] The additional elements can be solder pads, metallic elements or solder resist segments.

[0050] The metallic elements can be designed as copper pads.

[0051] According to a further embodiment, the circuit board is connected to the housing cap by a clamping connection.

[0052] The housing cap can have a base protruding from a base, which is, for example, circular in shape. The circuit board has corresponding holes that are guided onto the base and snap into place. The edges that define the hole in the circuit board deform slightly, creating a secure clamp connection. The circuit board, which is attached to the end of the housing cap, is then inserted into the grooves of the housing base. There, the circuit board can be mounted with play, since the clamp connection itself ensures that the circuit board is securely positioned.

[0053] According to a further variant of the invention, edge areas of the circuit board are bevelled so that a play-free positive fit is created when circuit boards are inserted into the holder.

[0054] According to an advantageous development of the invention, the circuit board has electrically conductive contact elements. When the circuit board is inserted into the receptacle, these contact elements are in contact with electrically conductive contact elements of the receptacle.

[0055] This contacting allows conductive connections to be established between components on the circuit board and other components inside the housing. A particular advantage is that the contacting occurs completely automatically when the circuit board is inserted into the desired position in the receptacle. Another advantage is that no additional assembly steps are required for contacting. Because the circuit board is securely clamped in the receptacle, secure contact between the contact elements of the circuit board and the receptacle is ensured.

[0056] For example, the contact elements of the circuit board are components or conductor tracks.

[0057] The contact elements of the circuit board can be made of copper or tinned or gold-plated.

[0058] Furthermore, the contact elements of the holder can consist of conductive coatings or of conductive, surface-treated materials.

[0059] Examples of this are aluminum parts with conductive, for example chromated, surface treatments or zinc die-cast parts with conductive, in particular nickel-plated or chrome-plated, surface coatings.

[0060] The invention is explained below with reference to the drawings. They show: Figure 1: Embodiment of the optical sensor according to the invention in the form of a light curtain. Figure 2: Embodiment of a printed circuit board insertable into grooves of a housing with a film hinge a) with printed circuit boards partially extended from the grooves. b) with printed circuit boards inserted into the grooves. c) Sectional view of the arrangement according to Figure 2b . Figure 3a:Variant of the circuit board according to Figure 2 . Figures 3b-e: Different designs of the film hinges of the printed circuit board according to Figure 3a as well as different grooves. Figure 4a: Arrangement with a housing base and a housing cap for play-free mounting of a printed circuit board. Figure 4b: Sectional view of the housing cap of the arrangement according to Figure 4a. Figure 5: First variant of the arrangement according to Figure 4a Figure 6: Second variant of the arrangement according to Figure 4a Figure 7: Third variant of the arrangement according to Figure 4aFigure 8a: Illustration of a printed circuit board mounted at an angle on a housing cap. Figure 8b: Individual illustration of a housing cap according to Figure 8a associated housing base body. Figure 8c: Representation of the assembled units of the Figures 8a, 8b . Figures 9a-c: Variant of the embodiment of the Figures 8a to 8c . Figure 10: Example of a housing cap with associated printed circuit board a) for producing a clamping device between the housing cap and the printed circuit board. b) after producing a clamping device between the housing cap and the printed circuit board. c) Individual representation of the printed circuit board in a top view. Figure 11: a) Example of a printed circuit board with a widened edge area b) Printed circuit board according to Figure 11a when inserted into grooves of a housing. c) Printed circuit board according to Figure 11a after insertion into grooves of a housing. Figures 12a-c: Variant of the embodiment according to Figure 11a to c.

[0061] Figure 1shows schematically the structure of an embodiment of the optical sensor according to the invention in the form of a light curtain 1 for detecting objects within a monitoring area.

[0062] The light curtain 1 comprises a transmitter unit with a housing 2a having a series arrangement of transmitters 4 emitting light beams 3 and transmitting optics 5 forming optical elements associated with these transmitters. Furthermore, the light curtain 1 comprises a receiver unit with a second housing 2b having a series arrangement of receivers 6 receiving light beams 3, each of which is preceded by an optical element in the form of a receiving optics 7.

[0063] The housings 2a, 2b are arranged at opposite edges of the monitored area such that a receiver 6 is arranged opposite a transmitter 4, forming a transmitter-receiver pair with the transmitter, with the light beams 3 of the transmitter 4 forming a beam axis. In the present case, eight beam axes are provided. Of course, the light curtain 1 can also have a different number of beam axes.

[0064] Alternatively, the light curtain 1 can also be designed as a reflective light curtain. In this case, all transmitters 4 and receivers 6 are arranged in a housing 2a, which is located at one edge of the monitored area. A reflector is located at the other end. When the monitored area is clear, the light beams 3 from the transmitters 4 are guided back to the respective assigned receiver 6 via the reflector.

[0065] The transmitters 4 are controlled by a transmitter controller 8. An evaluation unit 9 is assigned to the receivers 6. The beam axes are activated cyclically, one after the other. The evaluation unit 9 controls the receivers 6 and evaluates their received signals to generate an object detection signal in the form of a binary switching signal, the switching states of which indicate whether or not an object is located in the monitored area. If the monitored area is clear, the light beams 3 of the beam axes reach the receiver 6 of the respective beam axis unhindered. If an object interferes with the beam, at least one beam axis is interrupted. The evaluation unit 9 can have a multi-channel structure if the light curtain 1 forms a safety sensor.

[0066] The transmitters 4 and receivers 6 form sensor components of the optical sensor. The transmitter controller 8 and the evaluation unit 9 form electronic components of the optical sensor. The sensor components and electronic components are arranged on printed circuit boards 10, which, according to the invention, are mounted in receptacles of the housings 2a, 2b without play in that, when the printed circuit board 10 is inserted into the respective receptacle, elements of the receptacle or elements of or on the printed circuit board 10 are deformed. Exemplary embodiments of this are shown in the Figures 3 - 16 for the housing 2b of the receiver unit, whereby the same requirements are also provided for the housing 2a of the transmitter unit.

[0067] Figure 2a shows a receptacle of the housing 2b, in the form of grooves 11, into which a printed circuit board 10 can be inserted. The grooves 11 run parallel and spaced apart from one another.

[0068] A film hinge 12 is provided at one edge of the circuit board 10, which is formed integrally with the circuit board 10 and is separated from the body part of the circuit board 10 by a recess 13. The film hinge 12 protrudes laterally beyond the edge of the circuit board 10.

[0069] If the circuit board 10 is inserted into the grooves 11, the film joint 12 is clamped between the body part of the circuit board 10 and the groove 11, whereby the circuit board 10 is fixed in a desired position ( Figures 2b, 2c ). By clamping, a force indicated by an arrow in Figure 2c marked spring force, which fixes the circuit board 10 in the grooves 11.

[0070] Figure 3a shows a variant of the printed circuit board 10 according to the Figures 2a - 2cIn this case, the recess 13, which separates the film joint 12 from the body part of the circuit board 10, is circularly widened in its rear area. By specifying the width of the film joint 12 and the size of the recess 13, the elastic properties of the film joint 12 can be specified.

[0071] The Figures 3b - 3e show different cross sections of the film joint 12 and the groove 11. The directions of the contact forces acting when the film joint 12 is pressed into the groove 11 are marked with double arrows.

[0072] In the statements of the Figures 3b - 3d The groove 11 has a rectangular cross-section. In the embodiment of the Figure 3e the groove 11 has a conical cross-section, which additionally provides a stabilizing force of the circuit board 10 perpendicular to the circuit board plane.

[0073] In the embodiments of the figures of the Figures 3b, 3ethe boundary surfaces of the film hinge 12 are not chamfered, i.e. they run parallel to the boundary surfaces of the body part of the circuit board 10 and to the bottom part 22 of the groove 11. In the embodiments of the Figures 3c, 3d These interfaces are chamfered, i.e. they run obliquely to the interfaces of the body part of the circuit board 10 and to the bottom part 22 of the groove 11. Accordingly, the contact forces in the embodiments of the Figures 3b, 3e in the circuit board level, in the embodiments of the Figures 3c, 3d diagonally to this.

[0074] The Figures 4a, bshow an embodiment in which the housing has a housing base body 14 and a housing cap 15, with which an opening in the housing base body 14 can be closed. The printed circuit board 10 can be inserted into grooves 11 (not shown separately) of the housing base body 14, wherein the printed circuit board 10 can be mounted there with play. The position of the printed circuit board 10 is fixed in the housing cap 15.

[0075] As the Figures 4a, 4b As shown, the circuit board 10 has a resilient circuit board section 16 that forms a resilient joint. This is pressed against a wall of the housing cap 15 by a block-shaped form-locking element 17, whereby the circuit board 10 is fixed in position without play. The form-locking element 17 is mounted in a recess between the resilient joint and another segment of the circuit board 10.

[0076] Electrically conductive contact elements 18 can be arranged on the circuit board 10, wherein Figure 4a Several configuration options are shown. When the printed circuit board 10 is fixed in the desired position by placing the housing cap 15 on the housing cap 15, the contact elements 18 are automatically electrically contacted with corresponding contact elements 18 (not shown) in the housing cap 15. This creates, in particular, an electrically conductive connection between components on the printed circuit board 10 and electrical connection means, such as a cable connection (not shown) in the housing cap 15.

[0077] Corresponding contact elements 18 can also be provided in all other embodiments.

[0078] The Figures 5 - 7 show variants of the arrangement according to the Figures 4a, bwhich differ in the design of the form-locking element 17 and the coupling of the printed circuit board 10 to this form-locking element 17.

[0079] The Figures 8a - 8c show a further embodiment of a play-free mounting of the printed circuit board 10 in a receptacle of the housing 2b. The housing again comprises a housing base body 14 with grooves 11 for receiving the printed circuit board 10 and a housing cap 15. The printed circuit board 10 is coupled to the housing cap 15 via elastically deformable coupling means 19, which form a resilient joint, in such a way that the printed circuit board edges run obliquely to the longitudinal axis of the housing cap 15. The coupling means 19 are mounted in a receiving block 20 of the housing cap 15.

[0080] During assembly, the printed circuit board 10 is inserted into the grooves 11 of the housing base body 14, with the printed circuit board plane lying in the plane of the grooves 11. Since the printed circuit board 10 lies diagonally in the housing cap 15, when the housing cap 15 is placed on the housing base body 14, the spring-loaded joint is deflected and the printed circuit board 10 is tensioned and clamped in the grooves 11, thus supporting it without play.

[0081] The Figures 9a - 9c show a variant of the embodiment according to Figures 8a - c. In the present case, the printed circuit board 10 is directly connected to the receiving block 20. Otherwise, the arrangement of the Figures 9a - c the arrangement according to the Figures 8a - c . Since the circuit board 10 itself is elastically deformable, it takes over the function of the spring-loaded joint.

[0082] The Figures 10 a-cshow a further example of a play-free coupling of the printed circuit board 10 to the housing cap 15. The printed circuit board 10 has a circular bore 21, as in particular Figure 10c A circular disk-shaped base 23 protrudes from a base part 22 of the housing cap 15. The printed circuit board 10 is then guided by tilting toward the base part 22, and the hole 21 is engaged in the base 23.

[0083] The recess (21) in the circuit board and the base (23) do not necessarily have to be a hole, but can also be shaped differently.

[0084] The Figures 11a - 11c show a further embodiment for the play-free mounting of the circuit board 10 in grooves 11 of the housing 2b.

[0085] How Figure 11aAs shown, the edge regions of the printed circuit board 10 are widened at one end. Laterally protruding printed circuit board segments 24a, b are provided there, whereby it is essential that these printed circuit board segments 24a, b are provided at different heights of the printed circuit board 10.

[0086] To mount the circuit board 10, it is inserted diagonally with the circuit board segments 24a, b into the grooves 11 ( Figure 11b ). Since the circuit board segments 24a, b are located at different heights, this can be accomplished without jamming the circuit board segments 24a, b in the grooves 11. The circuit board 10 is then tilted into the plane of the grooves 11. In this desired position, which is fixed when the housing cap 15 is placed on the housing base body 14, the circuit board segments 24a, b clamp into the grooves 11 and ensure secure positioning of the circuit board 10 ( Figure 11c ).

[0087] The Figures 12a - cshow a variant of the arrangement of the Figures 11a -c In this case, solder pads 25a, b or soldered components are provided as elevations in the widened edge areas of the printed circuit board 10 instead of the printed circuit board segments 24a, b. (24a,b)PCB segment (25a,b)Solder pad (26) Spring joint (27) Film joint receptacle (28) Mandrel (28a) Groove with mandrel-like edges (28b) Chamfer on the PCB (29) Recess (30) Projection

Claims

1. An optical sensor for detecting objects within a monitoring area, having sensor components and electronic components which are arranged in at least one housing (2a, 2b) in which at least one printed circuit board (10) accommodating sensor components and / or electronic components is mounted, characterised in that in that the printed circuit board (10) is mounted free of play in a receptacle of the housing (2a, 2b), in that elements on the printed circuit board (10) are deformed when the printed circuit board (10) is brought into a desired position in the receptacle, the elements on the printed circuit board (10) being deformable in the receptacle in such a way that they are mounted free of play in the receptacle.

2. An optical sensor according to claim 1, characterised in that the printed circuit board (10) forms a resilient joint as a deformable element in an edge region, which can be deflected by deformation and which can be brought into engagement with the receptacle.

3. An optical sensor according to claim 2, characterised in that the resilient joint is a film joint (12) formed integrally with a flat body part of the printed circuit board (10) and set off from the latter by a recess (13).

4. An optical sensor according to claim 3, characterised in that in a rest position the film joint (12) projects laterally beyond the edge of the body part, and in that when the printed circuit board (10) is inserted into a groove (11) forming the receptacle, the film joint (12) is pressed between the body part and the groove (11), as a result of which the printed circuit board (10) is mounted in the receptacle without play.

5. An optical sensor according to claim 4, characterised in that the film joint (12) has at least one chamfer (12a), whereby the film joint (12) is additionally deflected perpendicularly or obliquely to the plane of the printed circuit board (10) when the printed circuit board (10) is mounted in the groove (11).

6. An optical sensor according to one of claims 4 or 5, characterised in that the receptacle has two grooves (11) which run parallel to one another and are arranged in the housing (2a, 2b) and in which opposite edges of the printed circuit board (10) are mounted.

7. An optical sensor according to claim 2, characterised in that the housing (2a, 2b) has a housing base body (14) and a housing cap (15) which can be placed on an opening of the housing base body (14), wherein opposite edge regions of the printed circuit board (10) can be mounted in grooves (11) of the housing base body (14), which are components of the receptacle.

8. An optical sensor according to claim 7, characterised in that the resilient joint of the printed circuit board (10) is mounted without play on an inner end wall of the housing cap (15).

9. An optical sensor according to claim 8, characterised in that the resilient joint is mounted without play on the inner wall of the housing cap (15) by means of a positive-locking element (17).

10. An optical sensor according to claim 9, characterised in that the resilient joint is deflected out of the plane of the printed circuit board (10) by the positive locking element (17).

11. An optical sensor according to claim 7, characterised in that an end-face section of the printed circuit board (10) is mounted in the housing cap (15) by means of the resilient joint in such a way that the printed circuit board (10) is arranged at an angle to the longitudinal axis of the housing cap (15) and that, after insertion of the printed circuit board (10) into the grooves (11) of the housing base body (14), the resilient joint is bent, as a result of which the edge regions of the printed circuit board (10) are mounted under tension in the grooves (11).

12. An optical sensor according to claim 11, characterised in that the resilient joint is a separate element adjoining the front edge of the printed circuit board (10).

13. An optical sensor according to claim 11, characterised in that the printed circuit board (10) itself forms the resilient joint.

14. An optical sensor according to claim 7, characterised in that the printed circuit board (10) has a region with widened edge regions, these edge regions having different heights.

15. An optical sensor according to claim 8, characterised in that the edge regions are arranged opposite one another on the printed circuit board (10).

16. An optical sensor according to one of claims 14 or 15, characterised in that, when the edge regions of the printed circuit board (10) are inserted obliquely into the grooves (11), the edge regions are guided with play in the grooves (11), and in that the edge regions of the printed circuit board (10) are clamped in the grooves (11) by aligning the printed circuit board (10) in the plane of the grooves (11).

17. An optical sensor according to one of claims 14 - 16, characterised in that local elevations in the edge regions of the printed circuit board (10) are components of the printed circuit board (10).

18. An optical sensor according to one of claims 14 - 16, characterised in that local elevations in the edge regions of the printed circuit board (10) are formed by additional elements.

19. An optical sensor according to claim 18, characterised in that the additional elements are solder pads, metallic elements or solder resist segments.

20. An optical sensor according to claim 7, characterised in that the printed circuit board (10) is connected to the housing cap (15) by a clamp connection.

21. An optical sensor according to one of claims 1 to 20, characterised in that the printed circuit board (10) has electrically conductive contact elements (18), wherein, when the printed circuit board (10) is inserted into the receptacle, these contact elements (18) are in contact with electrically conductive contact elements (18) of the receptacle.

22. An optical sensor according to claim 21, characterised in that the contact elements (18) of the printed circuit board (10) are components or conductor tracks.

23. An optical sensor according to one of claims 21 to 22, characterised in that the contact elements (18) of the printed circuit board (10) are made of copper or are tin-plated or gold-plated.

24. An optical sensor according to one of claims 21 to 23, characterised in that the contact elements (18) of the receptacle consist of conductive coatings or of conductive, surface-treated materials.

25. An optical sensor according to one of claims 1 to 24, characterised in that it is a safety sensor.