Apparatus and method for producing fibre bundles

Abstract

The present invention relates to an apparatus and a method for producing fibre bundles (2), the device comprising: a clamping device (3) for receiving and fixing a plurality of fibres (20); a pressing device (4) for applying a force to the clamping device (3); a pressing receptacle (40), arranged on the pressing device (4), for receiving the clamping device (3) and for compressing the plurality of fibres (20) arranged in the clamping device (3); and at least one radiation source (5), the beam path (50) of which is directed onto a region in or adjacent to the clamping device (3) in order to connect, in particular to fuse, the plurality of fibres (20) received in the clamping device (3) to one another.

Description

[0001] Device and method for producing fiber bundles

[0002] Technical area

[0003] The present invention relates to an apparatus and a method for producing fiber bundles.

[0004] State of the art

[0005] Fiber bundles are used in many applications to transmit information and services. For example, fiber bundles are used in light or laser radiation in light projectors and laser systems, as well as in spectroscopy and surface analysis. The transmission direction is freely selectable and can range from one input connector to multiple output connectors, from multiple input connectors to a bundled output connector, or from multiple connectors on one side to multiple connectors on the other side, whereby the number of fibers per connector can vary.

[0006] Fiber bundles are also used for beam transformation. The light is transmitted from one geometry to another (e.g., different aspect ratio, circular / elliptical, polygonal, etc.). Other common applications of fiber bundles are systems such as multimode beam combiners. These contain at least one optical fiber with a step-index or graded-index, or a combination of both, in which a refractive index difference is selected at the core-cladding interface to create a numerical aperture that enables stable and uniform beam output. One or more such fibers are formed into a bundle. The fibers in the bundle can, in turn, be separated by appropriate cladding to be optically coupled or decoupled.Illumination systems can comprise a plurality of such fibers coupled to a plurality of laser diodes or other light sources. For example, conical couplers can contain a plurality of optical fibers (or other waveguides) arranged in a rectangular, round, square, or hexagonal configuration. Typically, each of the fibers has the same cross-sectional dimension. Alternatively, fibers of different geometries, particularly different cross-sectional dimensions, can be combined. In known variants, the fibers are square, round, or trapezoidal in cross-section. Combinations of different fiber types, such as double-clad, gradient-index, or step-index fibers, are also known.

[0007] Although optical fibers are used in many practical examples, other waveguide structures, such as planar waveguides, can also be configured to define a coupling surface. Common examples include rectangular double-clad fibers, rectangular step-index fibers, or other fibers that are tapered, and / or bonded or fused. Conventional optical fibers are formed by thermally fusing an output end portion of a bundle of optical fiber strands. By arranging the fiber optic strands in a polygonal, for example, hexagonal, dense structure at the time of thermal fusion, it is possible to reduce their diameter or increase the fill factor. In the case of a fusion-bonded structure, the affected section exhibits improved heat resistance.

[0008] Methods and corresponding devices for processing an optical fiber are also known. A fiber core of the optical fiber is heated to a fiber core temperature within the glass transition temperature range of the fiber core using at least the light from the directed light source. Furthermore, losses cause heating, which can lead to destruction at certain locations, or at least to undesirable heating.

[0009] Common methods use either a flame or an electric plasma for fusion. Both methods have the disadvantage that, especially with larger bundles, heat is introduced from the outside into the bundle and transported to the interior of the bundle by heat conduction. Reducing the heat from the outside to protect the fibers in the outer area of ​​the bundle can result in insufficient heat reaching the interior of the bundle, and the inner fibers are not sufficiently fused. Conversely, a high heat input from the outside can lead to the inner fibers being fused but the outer fibers being thermally overstressed.

[0010] Description of the invention

[0011] In the following, the term "a plurality of fibers" refers to a plurality of individual fibers in an unconnected state. The term "fiber bundle," on the other hand, refers to a plurality of fibers in a connected state.

[0012] Based on the known prior art, it is an object of the present invention to provide an improved device for producing fiber bundles and a corresponding method.

[0013] The object is achieved by a device for producing fiber bundles having the features of claim 1. Advantageous further developments emerge from the subclaims, the description, and the figures.

[0014] Accordingly, a device for producing fiber bundles is proposed. According to the invention, the device comprises a clamping device for receiving and securing a plurality of fibers, a pressing device for applying a force to the clamping device, a pressing receptacle arranged on the pressing device for receiving the clamping device and for pressing the plurality of fibers arranged in the clamping device, and at least one radiation source whose beam path is directed toward a region in or adjacent to the clamping device in order to interconnect, in particular to fuse, the plurality of fibers received in the clamping device.

[0015] The clamping device allows the loose fibers, which represent the starting product for the present device, to be positioned and fixed relative to one another. A clamping force emanating from the clamping device contributes to the fiber cladding surfaces being pressed together. Due to the clamping force of the clamping device, a certain deformation of the fiber cladding surfaces can occur during heating, thereby increasing the contact surface area between the fibers. This effect can be amplified by the forces acting on the clamping device from the pressing device, so that the contact surface area between the fibers is increased even further. The pre-positioning of the fibers relative to one another using the clamping device also has the advantage that the force acting on the fibers from the pressing device can be optimally utilized.In particular, the clamping device ensures that the individual fibers are arranged substantially parallel to one another, so that the largest possible contact surface between the fibers can be created during compression by means of the compression device during heating. In the case of a large number of originally round fibers, for example, these assume a substantially polygonal, in particular hexagonal, peripheral shape during heating and compression by means of the compression device. As a result, a larger fill factor can be achieved with respect to the large number of fibers. The effect described above can be further improved by using polygonal fibers.

[0016] In a further preferred embodiment of the device, the clamping device is configured to exert a force on the plurality of fibers that is perpendicular to the circumferential surface or with respect to the longitudinal axis of the plurality of fibers. Such a force exerted on the fibers has the advantage that the fibers maintain their position. This also applies to a plurality of fibers that do not have an outer glass cladding. The fibers are firmly positioned relative to one another and relative to the radiation source. The clamping device exerts an external force on the plurality of fibers that is uniform over the entire circumference. Such a force has the advantage that the fibers are not displaced by the applied force, but rather are pressed together. Accordingly, the gaps between the fibers can be reduced or even completely eliminated during heating by the radiation source.This results in a reduced diameter of the produced fiber bundle compared to that of the plurality of fibers by reducing the spaces not lined with fibers, increases the contact surface between the individual fibers and enables an increased irradiance per unit area.

[0017] In a preferred embodiment, the radiation source is configured to irradiate at least one defined point in the clamping device and / or adjacent to the clamping device in order to connect individual fibers of the plurality of fibers in a defined manner, wherein the radiation source and / or the press receptacle are movable relative to one another, in particular radially and / or axially, for this purpose. In conjunction with the clamping force emanating from the clamping device and the pressing device, the greatest possible contact between the fiber cladding surfaces of the individual fibers can be provided during heating in order to fuse the individual fibers together. Furthermore, the defined irradiation of the plurality of fibers allows the fibers to be heated, for example, from the inside out. In particular, the inner fibers can be sufficiently heated without excessive thermal stress on the outer fibers.

[0018] With a small number of fibers (e.g., < 10 fibers) or with fibers with a comparatively large diameter (e.g., diameter > 100 pm), it may be sufficient for the radiation source to irradiate only the contact surfaces of the fibers to fuse them together. Heating across the entire fiber cross-section of the individual fibers is therefore unnecessary. Damage to the individual fibers that can occur in connection with heating the fibers, such as an unwanted change in the fiber structure within, can thus be reduced or avoided.

[0019] As a result, a small number of fibers can be irradiated using the present device only to the extent necessary to interconnect the adjacent fiber cladding surfaces to form a fiber bundle. Fiber regions of one of the plurality of fibers that are not involved in forming a connection to an adjacent fiber, such as the fiber core or a fiber cladding surface forming an outer surface of the plurality of fibers, can be spared from irradiation and the associated heating.

[0020] In a further embodiment, the radiation source is a laser, preferably a diode laser, a CO laser, or a CO2 laser, wherein in particular the diode laser has a wavelength in the range of 2 pm - 3.5 pm, the CO laser has a wavelength in the range of 4.8 pm to 8.3 pm, preferably 5.5 pm, and the CO2 laser has a wavelength in the range of 9.6 pm to 10.6 pm. CO lasers, CO2 lasers, or diode lasers as radiation sources are characterized by their high energy input in a defined beam diameter and low scattering effects. By using a CO laser or CO2 laser as the radiation source, it is possible to introduce the radiation energy in a defined manner into the plurality of fibers held in the clamping device. In particular, the prestress provided by the clamping device and the pressing device can be used to provide a deformation of the plurality of fibers after appropriate heating.This allows for the greatest possible contact between the fiber cladding surfaces of the individual fibers, thus ensuring optimal fusion of the individual fibers. The defined irradiation of the multitude of fibers enabled by the aforementioned lasers allows the fibers to be heated, for example, from the inside out. In particular, the inner fibers can be sufficiently heated without excessive thermal stress on the outer fibers.

[0021] With a small number of fibers (e.g., <10 fibers), it may be sufficient for the diode laser, CO laser, or CO2 laser to irradiate only the contact surfaces of the fibers to fuse them together. Complete heating or melting of the large number of fibers is not necessary. Negative effects that can result from complete heating or melting of the large number of fibers, such as the formation of pores inside the individual fibers, can thus be reduced or avoided.

[0022] In a further preferred embodiment of the described device, the pressing device comprises a vacuum container which, when a vacuum is present in the vacuum container, is configured to exert a force on a cavity defined by the pressing receptacle, in particular on the clamping device arranged in the pressing receptacle. This embodiment has the advantage that the force transmitted from the pressing device to the clamping device and thus acting on the fibers perpendicular to the circumferential surface or with respect to the longitudinal axis of the plurality of fibers can be significantly increased. Due to a negative pressure prevailing in the vacuum container, the clamping device surrounding the fibers can be at least partially drawn into the vacuum container and thus additionally compressed. This compression affects the plurality of fibers and additionally holds them together.This, in turn, locks the fibers and further contributes to reducing the gaps between the individual fibers, thus increasing the fill factor. Furthermore, this contributes to reducing the diameter of the multitude of fibers, increasing the contact surface between the individual fibers, and increasing the irradiance per unit area. With regard to irradiation by means of the radiation source, heating or cooling may be necessary.

[0023] Fusion of the fibers under vacuum leads to comparatively less bubble formation.

[0024] In a further preferred embodiment of the described device, the clamping device is arranged substantially concentrically to the press receptacle in the radial direction and at least partially overlaps it in the axial direction. Such an embodiment has the advantage that the clamping device remains arranged in the intended position relative to the press receptacle and, accordingly, to the pressing device and the radiation source. Furthermore, a wide variety of clamping device designs can be used. The modular principle offers the possibility of using a wide variety of clamping devices and pressing devices, for example, with different inner diameters for a variable number of fibers to be inserted, but also with different axial lengths.

[0025] In a further exemplary embodiment of the described device, the clamping device comprises an elastomer that is transparent and / or partially transparent and temperature-resistant, preferably up to the melting point of glass, particularly preferably 1,400°C. Formations of the clamping device made of an elastomer enable the exertion of radial pressure or pressure acting perpendicularly to the longitudinal axis of the plurality of fibers on the plurality of fibers. The clamping device can be removed again after the plurality of fibers have been connected to form a fiber bundle. An elastomer-based clamping device can be adapted relatively easily to the geometries of a fiber bundle, both to fibers with and without sheathing. First, a positive mold of the finished fiber bundle is created. The elastomer is then cast around the positive mold.The cured elastomer forms the finished, flexible clamping device. In the next step, the plurality of fibers is introduced into the clamping device, for example, clamped into it, thereby stretching the clamping device, i.e., the elastomer.

[0026] Alternatively, if the clamping device and the compression fitting are implemented as a combined unit, the plurality of fibers is arranged laterally in a recess of a clamping device. A body movable in the recess perpendicular to the fiber's longitudinal axis can exert a force acting perpendicularly on the peripheral surface or with respect to the longitudinal axis of the plurality of fibers by its displacement. A uniform distribution of the pressure is enabled over a defined length of the clamping device in the axial direction of the fibers. Furthermore, a transparent or semi-transparent elastomer allows the energy introduced via the radiation source to pass through to the plurality of fibers. When the plurality of fibers is heated by the radiation source, the pressure or prestress emanating from the clamping device causes the heated fibers to be compressed.Furthermore, elastomers also exhibit a certain degree of heat resistance, which is necessary during the bonding process, especially during fiber fusion. The clamping devices for this device can be sleeve-shaped, particularly in a modular system with different dimensions and geometries (e.g., tubular, cuboid, etc.). All that is required is a positive of the desired fiber bundle geometry.

[0027] In a further embodiment, the clamping device is tubular and, in particular, has a stepped shape to provide two regions with different cross-sections. The clamping device can thus be adapted easily and inexpensively to the geometry of a transition region, so that a sufficiently radial or substantially uniform pressure acting perpendicular to the longitudinal axis of the plurality of fibers can be ensured in this region as well during heating of the plurality of fibers.

[0028] In a further preferred embodiment, the orientation of the beam path of the radiation source is different from the fiber orientation of the plurality of fibers, preferably perpendicular to the fiber orientation of the plurality of fibers. This has the advantage that the fibers can be connected in a defined manner at the designated locations, thus achieving high irradiation efficiency. In addition, the position of the fusion region along the axial direction of the fibers can be controlled by axially displacing the fibers and / or by axially displacing the radiation source. The defined irradiation of the plurality of fibers enabled by the radiation source allows the fibers to be heated, for example, from the inside out. In particular, the inner fibers can be sufficiently heated without excessive thermal stress on the outer fibers.

[0029] In addition, the position of the fusion region can be controlled, for example in the circumferential direction of the fiber, by shifting the radiation source in the direction of the fiber circumference, i.e. along an orbit of the plurality of fibers or of a single fiber, or by rotating the plurality of fibers in the direction of the fiber circumference. In the case of a small number of fibers (e.g. < 10 fibers), the fibers no longer need to be heated completely, which contributes to a reduction in the deformation of the fibers. The heating of the fibers can be reduced to their edge regions in order to achieve a connection. In addition, different regions in the cross-section of the fibers can be processed by inclining the radiation source relative to the fibers or inclining the fibers relative to the radiation source, as well as by appropriately selecting the power of the radiation source.

[0030] In a further preferred embodiment, the beam path of the radiation source is arranged substantially in the fiber orientation of the plurality of fibers. In other words, the laser is directed onto the ends of the plurality of fibers, whereby an end portion of the plurality of fibers can be heated and the ends of the plurality of fibers can be fused together. The radiation energy can be precisely introduced by positioning the radiation source along the fiber alignment in the cross-section and adapted to the fiber geometry. A homogeneous and complete connection of the fibers can be achieved even in the non-circumferentially arranged regions. Furthermore, by adjusting the beam cross-section, specific regions in the cross-section of the fibers can be left untreated or treated gently.

[0031] In a further preferred embodiment, the device comprises a scanning device for the defined deflection of the laser beam. The scanning device allows the focal point of the laser beam to be controlled or regulated in a defined manner. As a result, the plurality of fibers can be heated or melted in a defined manner. In particular, the scanning device comprises at least two mirrors for the defined control of the focal point of the laser beam.

[0032] In a further preferred embodiment, the device comprises a detection device for detecting at least one fiber parameter of the plurality of fibers or of the connected fiber bundle, wherein in particular the detection device is connected to a control / regulation unit.

[0033] The detection device can detect the position and orientation of the adjacent surfaces of the plurality of fibers. This information can then be forwarded to the control unit. Based on the fiber parameters determined by the detection device, the control unit can then specify the exact position(s) within the plurality of fibers at which the radiation source should heat or fuse the individual fibers together. As a result, such a detection device enables optimized process monitoring and control of the joining of the plurality of fibers. In addition, process parameters and critical control points can be monitored before, during, and after the joining process and compared with the respective target parameters.Furthermore, a detection device provides the ability to make necessary adjustments if the target parameters fall below or exceed the specified values. Furthermore, the ability to regulate the parameters during the bonding process is advantageous. For example, unwanted overheating of the fibers can be prevented by a control unit integrated into the radiation source. In addition, if the bond is unsatisfactory, a new irradiation or a more energy-intensive irradiation can be performed subsequently. The detection device can include, for example, a thermal imaging camera.

[0034] In a further preferred embodiment of the device, the at least one or the plurality of fiber parameters comprise the temperature, a temperature range, a degree of bonding, the shape, and / or the dimensions of the plurality of fibers or the fiber bundle. Knowledge of fiber bundle parameters such as the specific shape and size of the fibers enables energy-efficient application of the beam power as well as gentle bonding tailored to the individual fibers. The temperature range that leads to bonding, in particular fusion, of the fibers can thus be optimally achieved, and unnecessary overheating, which could lead to destruction of the fiber structure, can be avoided. In addition, undershooting the temperature required to bond the fibers, which could lead to an unsatisfactory or non-existent degree of fusion, can be avoided by readjusting the parameters.

[0035] The object is further achieved by a method for producing fiber bundles having the features of claim 14. Advantageous developments of the method emerge from the subclaims as well as the present description and the figures.

[0036] Accordingly, a method for producing fiber bundles is proposed. The method comprises receiving and securing a plurality of fibers in a clamping device, positioning the clamping device and the plurality of fibers arranged therein in a press receptacle arranged in a pressing device, compressing the clamping device and the plurality of fibers arranged therein by means of the pressing device, and fusing the plurality of fibers received in the clamping device to one another by means of at least one radiation source whose beam path is directed onto a region of the plurality of fibers in the clamping device or adjacent to the clamping device.

[0037] The clamping device allows the loose fibers, which represent the starting product for the present process, to be positioned and fixed relative to one another. A clamping force emanating from the clamping device contributes to the fiber cladding surfaces being pressed together. Due to the clamping force of the clamping device, a certain deformation of the fiber cladding surfaces can occur during heating, thereby increasing the contact surface area between the fibers. This effect can be amplified by the forces acting on the clamping device from the pressing device, so that the contact surface area between the fibers is increased even further. Pre-positioning the fibers relative to one another using the clamping device also has the advantage that the force acting on the fibers from the pressing device can be optimally utilized.In other words, the clamping device ensures that the individual fibers are arranged essentially parallel to one another, so that the largest possible contact surface between the fibers can be created during compression by the compression device and simultaneous heating by the radiation source. In the case of a large number of originally round fibers, these assume a substantially polygonal, for example, hexagonal, peripheral shape during heating and compression by the compression device. As a result, a larger fill factor can be achieved with respect to the large number of fibers.

[0038] In a further preferred embodiment of the described method, the pressing device comprises a vacuum container, and the step of positioning the clamping device and the plurality of fibers arranged therein in a press receptacle arranged in a pressing device comprises feeding the plurality of fibers into the vacuum container via the press receptacle. The step of pressing the clamping device and the plurality of fibers arranged therein together by means of the pressing device comprises generating a negative pressure in the vacuum container in order to press the plurality of fibers together, in particular in the region of the clamping device, during heating by means of the radiation source, in particular to press them together radially or perpendicularly with respect to the longitudinal axis of the plurality of fibers.

[0039] The force transmitted from the pressing device to the clamping device, which thus acts perpendicularly on the circumferential surface or with respect to the longitudinal axis of the plurality of fibers, can be significantly increased by additionally applying a negative pressure via the vacuum container. Due to a negative pressure prevailing in the vacuum container, the clamping device surrounding the fibers can, for example, be at least partially drawn into the vacuum container and thus additionally compressed radially. This leads to a reduction in the spaces between the fibers. Furthermore, a uniform force acting from the outside on the plurality of fibers has the advantage of holding the fibers in position. This type of force has the advantage that the fibers do not shift, but rather are held in their position.

[0040] In a further preferred embodiment of the described method, the step of fusing the plurality of fibers received in the clamping device to one another by means of at least one radiation source whose beam path is directed onto a region of the plurality of fibers in the clamping device or adjacent to the clamping device comprises a targeted heating, in particular a targeted melting, of defined regions within the plurality of fibers to produce predefined connection patterns, wherein the radiation source and / or the plurality of fibers arranged in the press holder are moved relative to one another, in particular radially and / or axially, for this purpose. For example, the achieved heating of the plurality of fibers allows the fibers to be heated, for example, from the inside out.In particular, the inner fibers can be sufficiently heated without placing excessive thermal stress on the outer fibers.

[0041] In addition, the pre-tensioning effect of the clamping device and the pressing device can be used to heat the plurality of fibers to ensure the greatest possible contact between the fiber cladding surfaces of the individual fibers.

[0042] With a small number of fibers (e.g., <10 fibers), it may be sufficient for the radiation source to only irradiate the contact surfaces of the fibers to fuse them together. Heating across the entire fiber cross-section of the individual fibers is therefore not necessary. Damage to the individual fibers that can occur in connection with heating the fibers, such as an unwanted change in the fiber structure within, can thus be reduced or avoided. As a result, the plurality of fibers can be irradiated using the present device only to the extent necessary to interconnect the adjacent fiber cladding surfaces and thus create a fiber bundle.Fiber regions of a fiber of the plurality of fibers that are not involved in the input of a connection to an adjacent fiber, such as the fiber core or a fiber cladding surface that forms an outer surface of the plurality of fibers, may be exempt from irradiation and the associated heating.

[0043] In a further preferred embodiment of the described method, the radiation source may comprise a diode laser, a CO laser or a CO2 laser to provide targeted fusion of predefined regions within the plurality of fibers.

[0044] The CO laser, CO2 laser, or diode laser are characterized by their high energy input in a defined beam diameter and low scattering effects. By using a CO laser or CO2 laser as the radiation source, it is possible to introduce the radiation energy in a defined manner into the multitude of fibers held in the clamping device. In particular, the prestress provided by the clamping device and the pressing device can be used to ensure the greatest possible contact between the fiber cladding surfaces of the individual fibers, thus optimally fusing the individual fibers. The defined irradiation of the multitude of fibers made possible by the above-mentioned lasers makes it possible to heat the fibers, for example, from the inside out. In particular, the inner fibers can be sufficiently heated without placing excessive thermal stress on the outer fibers.

[0045] With a small number of fibers (e.g., <10 fibers), it may be sufficient for the diode laser, CO laser, or CO2 laser to irradiate only the contact surfaces of the fibers to fuse them together. Complete heating or melting of the large number of fibers is not necessary. Negative effects that can result from complete heating or melting of the large number of fibers, such as the formation of pores inside the individual fibers, can thus be reduced or avoided.

[0046] In a further preferred embodiment, the fusion of the plurality of fibers is limited to a predefined fusion region, wherein, in particular, the length of the fusion region can be greater than the width of a cross-section of the plurality of fibers, and / or the fusion region is arranged at at least one end of the plurality of fibers. The geometric dimensions of the individual fibers and the shape of the fiber bundle have a significant influence on the transmission of the fiber bundle. In addition, excellent heat resistance, flexibility, and irradiation efficiency are achieved by a fusion region that is greater than the length of a cross-section of the fiber bundle and is arranged at at least one end of the fiber bundle.

[0047] In a further preferred embodiment, the individual fibers of the plurality of fibers can have a cladding, wherein the cladding of the fibers of the plurality of fibers is at least partially removed in the fusion region. In general, the light transmitted by the fibers is additionally coupled in at the end through the cladding. Additional fusion of the cladding of the fibers enables the transmitted light to pass beyond the cladding to an adjacent fiber. Therefore, fusion of the fibers in this transition region is also useful. This allows the fiber ends reduced to the core to be fused; alternatively, the fibers can also be fused in the rear region (where the cladding is still present).

[0048] Furthermore, a computer program product for carrying out the method described above is proposed.

[0049] Furthermore, a fiber bundle produced according to the method described above is proposed.

[0050] Short description of the characters

[0051] Preferred further embodiments of the invention are explained in more detail in the following description of the figures. In the figures:

[0052] Fig. 1 a shows schematically an apparatus for producing fiber bundles;

[0053] Fig. 1b shows a schematic diagram of a device for producing fiber bundles; Fig. 2 shows a schematic diagram of a device for producing fiber bundles;

[0054] Fig. 3 shows schematically an apparatus for producing fiber bundles;

[0055] Fig. 4a to 4e are schematic cross-sectional views of a plurality of fibers;

[0056] Fig. 5a to 5e show schematic paths of beams across the cross section of a plurality of fibers in a clamping device;

[0057] Fig. 6 schematically shows a perspective view of a beam path over a

[0058] A plurality of fibers in a clamping device;

[0059] Fig. 7 schematically shows a perspective view of a plurality of fibers in a

[0060] clamping device;

[0061] Fig. 8 schematically shows the transition region of three fibers from a coated to a non-coated region; and

[0062] Fig. 9a to 9c schematically show different connection combinations of fiber bundles.

[0063] Detailed description of preferred embodiments

[0064] Preferred embodiments are described below with reference to the figures. Identical, similar, or equivalent elements in the different figures are provided with identical reference numerals, and a repeated description of these elements is partially omitted to avoid redundancies.

[0065] Figure 1a schematically illustrates a device 1 for producing fiber bundles 20. The plurality of fibers 2 to be fused into a fiber bundle 20 is secured by a clamping device 3. This clamping device 3 is inserted via a press holder 40 into a vacuum container 42 provided with a pressing device 4.

[0066] The vacuum container 42 can be designed either modularly or as a solid part. In the embodiment shown in Figure 1, the vacuum container is formed with a lid and a base, which can be hermetically sealed via two connecting flanges 46, or in an alternative embodiment via a single connecting flange. The vacuum container 42 also has an intake port 44, via which any desired negative pressure can be generated in the vacuum container 42. In this embodiment, the pressing device 4 is cylindrically designed on the lid of the vacuum container 42. The pressing device 4 is mounted displaceably relative to the vacuum container 42, so that a relative movement relative to the radiation source 5 is possible. Furthermore, it is possible to change the positioning of the radiation source 5 both translationally and rotationally relative to the pressing device 4 or the clamping device 3.The pressing device 4 can be designed in any suitable form. Preferably, the pressing device 4 is modular. The pressing device 4 can be designed in the form of a chuck with radially arranged clamping jaws in order to apply a uniform force to the clamping device 3 in the circumferential direction of the clamping device 3.

[0067] The press receptacle 40 forms an opening assigned to the pressing device 4 in order to arrange the clamping device 3 in a desired position in the pressing device 4. The clamping device 3 and the plurality of fibers 2 arranged therein can thus be positioned or fixed relative to a radiation source 5 and its beam path 50. In this exemplary embodiment, the radiation source 5 is arranged perpendicular to the fiber alignment F, so that the beam path 50 of the radiation source 5 strikes the fibers 2 laterally. Furthermore, the radiation source 5 can be arranged at a different angle to the fiber alignment F and the beam path 50 can be deflected via optical equipment so that the beam path strikes the fibers 20 perpendicular to the fiber alignment F. The radiation source 5 is also detected and regulated via a control, ignition and regulation unit 60.The control, ignition, and regulation unit 60, in combination with a detection device 6, enables the position of the radiation source 5 and the intensity of the beam path 50 to be regulated. The detection device 6 can, for example, detect the dimensions of the individual fibers of the plurality of fibers, the course of the individual fibers, in particular the surface course, and / or the degree of fusion of the fibers 2 and transmit them to the control, ignition, and regulation unit 60. The detection device 6 can be designed to detect a wide variety of process parameters. The detection device 6 can, for example, be designed as a color image or infrared camera for detecting the temperature profile in the region of the plurality of fibers, but also in any other suitable embodiment for detecting process parameters.The control, ignition, and regulation unit 60 can be connected to other components of the device 1 and / or additional devices in order to control and regulate further process parameters, such as the vacuum of the vacuum container 42 or the setting parameters of the pressing device 4. Furthermore, the focus and focal point of the beam path 50 can be variably selected and adjusted using a scanning device 52, so that the beam path 50 can be readjusted if the position of the pressing device 4, the clamping device 3, and / or the radiation source 5 changes.

[0068] Figure 1b shows an alternative embodiment of a clamping device 3 and a pressing device 4, wherein the clamping device 3 and the pressing device 4 form a combined unit. The combined clamping device 3 and pressing device 4 comprises a pressing receptacle 40 into which the plurality of fibers 2 to be fused to form a fiber bundle is introduced. A displaceable body, for example a punch 41, arranged in the pressing receptacle 40 perpendicular to the fiber longitudinal axis is configured to exert a force acting perpendicularly on the peripheral surface or with respect to the longitudinal axis of the plurality of fibers by its displacement. The combined clamping device 3 and pressing device 4 can be combined with the further features of the device for producing fiber bundles according to Figure 1a.

[0069] Figure 2 schematically shows a further embodiment of a device 1 for producing fiber bundles 20. The embodiment shows the device 1 described in Figure 1 with a further exemplary arrangement of the radiation source 5 and its beam path 50 relative to the fiber alignment F. The radiation source 5 is positioned at an acute angle relative to the fiber alignment F. Accordingly, after passing the scanning device 52, the beam path 50 impinges obliquely on the plurality of fibers 20 to be fused. As long as the individual fibers of the plurality of fibers have not yet melted, the obliquely incident radiation is at least partially reflected within the plurality of fibers. The light reflected inside a fiber therefore leads to faster heating of the fiber by coupling it into the respective individual fiber.

[0070] Figure 3 schematically shows a further embodiment of a device 1 for producing fiber bundles 20. The embodiment shows the device 1 described in Figure 1 with a further exemplary arrangement of the radiation source 5 and its beam path 50 relative to the fiber alignment F. In the illustrated embodiment, the radiation source 5 is arranged such that its beam path 50 is aligned along the fiber alignment F. The beam path 50 strikes the cross-section of the plurality of fibers 20. The radiation source 5 can be arranged at any desired, suitable distance from the end of the fibers 20. Furthermore, the focusing and focal point of the beam path 50 can be variably selected and adjusted by means of a scanning device 52, so that the beam path 50 can be readjusted if the position of the pressing device 4, the clamping device 3 and / or the radiation source 5 changes.

[0071] Figures 4a to 4d show exemplary embodiments of arrangements of a plurality of fibers 20 of different geometries in a fiber bundle 2 surrounded by a sheath 24. In alternative embodiments, the fibers 20 can be arranged without a sheath 24, similarly to Figures 4a to 4d. This preferably applies to rectangular geometries of the plurality of fibers, since a sheath 20 is usually more difficult to implement in these cases. Furthermore, the sheath 24 can also be only partially removed in a melting region.

[0072] Figure 4a shows the cross-section of a plurality of fibers 20 comprising seven round fibers. The spaces 28 between the fibers 20 and between the fibers and the sheath 24 are also shown. Furthermore, the plurality of fibers 20 can also be realized in the arrangement shown in Figure 4a without a sheath 20 or with a sheath 20 partially removed at a melting area. The spaces 28 are to be reduced by heating, i.e., melting, coupled with forced deformation of the plurality of fibers by means of the clamping device and the pressing device.

[0073] Figure 4b shows an exemplary arrangement of four round-shaped fibers 20 surrounded by a square sheath 24. Furthermore, the plurality of fibers 20 can also be realized in the arrangement shown in Figure 4a without a sheath 20 or with a sheath 20 partially removed at a melting area. In Figure 4b, the plurality of fibers 20 is shown in the unfused state.

[0074] Figure 4c shows an exemplary arrangement of seven hexagonal fibers 20 arranged in a round sheath 24. Furthermore, the plurality of fibers 20 can also be realized in the arrangement shown in Figure 4a without a sheath 20 or with a sheath 20 partially removed at a melting region. The gaps 28 can be seen, which are smaller in the unfused state of the plurality of fibers 20 than in the case of round fibers, as shown, for example, in Figure 4a. Figure 4d shows four square fibers 20 surrounded by a square sheath 24. Furthermore, the plurality of fibers 20 can also be realized in the arrangement shown in Figure 4a without a sheath 20 or with a sheath 20 partially removed at a melting region.The gaps 28 can be seen, which are smaller in the unfused state of the plurality of fibers 20 than in the case of round-shaped fibers as shown, for example, in Figure 4a.

[0075] Figures 5a to 5e schematically show cross-sections through a plurality of fibers 20, each surrounded by a sheath 24 and secured by a circumferential clamping device 3. The radiation source 5, its beam path 50, as well as exemplary movements and the path of the beam path 50 in the cross-section of the fiber bundle 2 are shown. The arrow directions and paths are to be understood as exemplary embodiments. Any directions and paths are possible.

[0076] For example, Figure 5a schematically shows a spiral travel path of the radiation source 5 for precisely connecting the fibers 20 along the travel path. The movement of the radiation source 5 is only an example. Alternatively, to achieve the path of the radiation source shown in Figure 5a, the plurality of fibers 20 held in the clamping device 3 can be precisely shifted and rotated.

[0077] Figure 5b schematically shows a linear path of the irradiated positions within the cross-section of the plurality of fibers 20 held in the clamping device 3. For example, the fibers 20 can be connected in rows.

[0078] Figure 5c schematically shows a meandering path of the radiation source 5 projected onto the cross-section of the plurality of fibers 20 held in the clamping device 3.

[0079] Figure 5d shows a random path of the radiation source 5 projected onto the cross section of the plurality of fibers 20 held in the clamping device 3.

[0080] Figure 5e shows schematically a path of the irradiated positions within the

[0081] Cross-section of the plurality of fibers 20 held in the clamping device 3. In the embodiment shown in Figure 5e with fibers 20 of larger diameter, the edge regions of the fibers 20 to be fused are specifically irradiated.

[0082] The schematic representation of an embodiment according to Figure 6 shows a plurality of fibers 20 surrounded by a sheath 24 positioned in the clamping device 3. Furthermore, the plurality of fibers 20 can also be realized without a sheath 20 or with a sheath 20 partially removed at a melting region. The plurality of fibers 20 comprises a region (top in Figure 6) that has no sheath 24. The radiation source 5 is arranged at an angle to the orientation of the fibers 20. The embodiment shows a defined irradiation path. The irradiated positions and correspondingly connected regions of the fibers are arranged both in the axial direction and in the radial direction of the plurality of fibers 20.

[0083] Figure 7 schematically shows an embodiment for expanding the beam path 50 of the radiation source 5, directed onto a plurality of fibers 20, partially surrounded by a sheath 24 and a clamping device 3 (in the lower area of ​​Figure 7). Furthermore, the plurality of fibers 20 can also be implemented without a sheath 20. The expansion of the beam path 50 can be adapted to the cross-sectional area of ​​the plurality of fibers 20. Thus, both the entire cross-sectional area of ​​the plurality of fibers 20 and, in the case of a bundled beam path 50 of the radiation source 5, only certain points of the fibers 20 can be connected.

[0084] Figure 8 shows a section of a fiber bundle 2 with three fibers 20, which partially have a cladding 24 around each of the plurality of fibers 20, as well as a transition region 26 from cladding 24 to unclad fiber 20. The cladding 24 has been partially removed to reduce losses attributable to the core / cladding ratio. In the transition region from cladding to no cladding, scattering losses can occur due to uncontrolled escape of radiation. In particular, radiation can escape from the fiber in an uncontrolled manner, causing this region to heat up. To counteract the uncontrolled escape of radiation, these regions are typically filled with an adhesive. Furthermore, the application ensures a defined numerical aperture of the fiber core, which counteracts uncontrolled escape of radiation at the transition regions.Applying adhesive to the transition areas also leads to increased mechanical stability. For stability reasons, fusing the multitude of fibers 20 at this transition area is also advisable. One challenge here is the length of the fusing area, where the fiber ends, reduced to the core, are fused. Fusing a longer area also leads to increased stability of the fiber bundle 2 against mechanical stress due to a smaller bending angle of the individual fibers.

[0085] Figures 9a to 9c show schematic embodiments of possible combinations of a plurality of fibers 20 to form one or more fiber bundles 2. Fibers 20 can be connected in any possible combination using the described method.

[0086] Figure 9a shows a fiber bundle 2 comprising three individual fibers 20 which are connected or fused at both ends according to the method described above.

[0087] Figure 9b shows a fiber bundle 2. It has a connection of four fibers 2 at one end and is divided into two connections at the other end.

[0088] Figure 9c shows a fiber bundle 2 having two connections with four fibers 20 each at one end, which are connected in a combination to form three connections at the other end.

[0089] Where applicable, all individual features presented in the embodiments may be combined and / or exchanged without departing from the scope of the invention.

[0090] List of reference symbols

[0091] 1 device

[0092] 2 fiber bundles

[0093] 20 variety of fibers

[0094] 22 Merging area

[0095] 24 Sheathing

[0096] 26 Transition area

[0097] 28 space

[0098] 3 clamping device

[0099] 4 Pressing device

[0100] 40 Pressing fixture

[0101] 41 stamps

[0102] 42 vacuum containers

[0103] 44 intake manifold

[0104] 46 connecting flange

[0105] 5 Radiation source

[0106] 50 beam path

[0107] 52 Scanning device

[0108] 6 Detection device

[0109] 60 Control unit

[0110] F Fiber orientation

Claims

Claims 1. A device (1) for producing fiber bundles (2), comprising: a clamping device (3) for receiving and fixing a plurality of fibers (20); a pressing device (4) for providing a force to the clamping device (3); a pressing receptacle (40) arranged on the pressing device (4) for receiving the clamping device (3) and for pressing the plurality of fibers (20) arranged in the clamping device (3); and at least one radiation source (5), the beam path (50) of which is directed onto an area in or adjacent to the clamping device (3) in order to interconnect, in particular to fuse, the plurality of fibers (20) received in the clamping device (3).

2. Device (1) according to claim 1, wherein the clamping device (3) is configured to exert a force on the plurality of fibers (20) acting perpendicularly in particular with respect to the longitudinal axis of the plurality of fibers (20).

3. Device (1) according to claim 1 or 2, wherein the radiation source (5) is configured to irradiate at least one predetermined point in the clamping device (3) and / or adjacent to the clamping device (3) in order to connect individual fibers of the plurality of fibers (20) in a defined manner, wherein the radiation source (5) and / or the press holder (40) are movable relative to one another, in particular radially and / or axially, for this purpose.

4. Device (1) according to one of the preceding claims, wherein the radiation source (5) is a laser, preferably a diode laser, a CO laser or a CO2 laser, wherein in particular the diode laser has a wavelength in the range of 2 pm - 3.5 pm, the CO laser has a wavelength in the range of 4.8 pm to 8.3 pm, and the CO2 laser has a wavelength in the range of 9.6 pm to 10.6 pm.

5. Device (1) according to one of the preceding claims, wherein the pressing device (4) comprises a vacuum container (42) which is configured to exert a force on a cavity defined by the pressing receptacle (40), in particular on the clamping device (3) arranged in the pressing receptacle (40), when a vacuum is present in the vacuum container (42).

6. Device (1) according to one of the preceding claims, wherein the clamping device (3) is arranged in the radial direction substantially concentrically to the press receptacle (40) and at least partially overlaps therewith in the axial direction.

7. Device (1) according to one of the preceding claims, wherein the clamping device (3) comprises an elastomer which is transparent and / or partially transparent, and temperature-resistant, preferably temperature-resistant up to a melting temperature of glass of 1,400°C.

8. Device (1) according to one of the preceding claims, wherein the clamping device (3) is tubular, and in particular has a step shape in order to provide two regions with different cross-sections.

9. Device (1) according to one of the preceding claims, wherein the orientation of the beam path (50) of the radiation source (5) is not equal to the fiber orientation (F) of the plurality of fibers (20), preferably perpendicular to the fiber orientation (F) of the plurality of fibers (20).

10. Device (1) according to one of claims 1 to 8, wherein the beam path (50) of the radiation source (5) is arranged substantially in fiber orientation (F) of the plurality of fibers (20).

11. Device (1) according to one of the preceding claims, wherein the device (1) comprises a scanning device (52) for the defined deflection of the beam path of the laser source, wherein in particular by means of the scanning device (52) the focal point of the beam path can be controlled or regulated in a defined manner.

12. Device (1) according to one of the preceding claims, wherein the device (1) comprises a Detection device (6) for detecting at least one fiber parameter of the plurality of Fibers (20) or the connected fiber bundle (2), wherein in particular the detection device (6) is connected to a control unit (60).

13. Device (1) according to the preceding claim, wherein the at least one or a plurality of fiber parameters relate to the temperature, a temperature range, a degree of connection, the shape, and / or the dimensions of the plurality of fibers (20) or the fiber bundle (2).

14. A method for producing fiber bundles (2), comprising the steps of: a) receiving and fixing a plurality of fibers (20) in a clamping device (3); b) positioning the clamping device (3) and the plurality of fibers (20) arranged therein in a press receptacle (40) arranged in a pressing device (4); c) pressing the clamping device (3) and the plurality of fibers (20) arranged therein together by means of the pressing device (4); and d) fusing the plurality of fibers (20) received in the clamping device (3) to one another by means of at least one radiation source (5) whose beam path (50) is directed onto a region of the plurality of fibers (20) in the clamping device (3) or adjacent to the clamping device (3).

15. The method according to claim 13, wherein the pressing device (4) comprises a vacuum container (42) and step b) comprises feeding the plurality of fibers (20) into the vacuum container (42) via the press receptacle (40), and wherein step c) comprises generating a negative pressure in the vacuum container (42) in order to press the plurality of fibers (20) together, in particular in the region of the clamping device (3), in particular or to press them together perpendicularly with respect to the longitudinal axis of the plurality of fibers.

16. The method according to any one of claims 13 to 16, wherein step d) comprises a targeted heating, in particular a targeted melting, of defined regions within the plurality of fibers (20) to produce predefined connection patterns, wherein the For this purpose, the radiation source (5) and / or the plurality of fibers (20) arranged in the press holder (40) are moved relative to one another, in particular radially and / or axially.

17. The method according to any one of claims 13 to 15, wherein the radiation source (5) comprises a CO laser or a CO2 laser to provide targeted fusion of predefined regions within the plurality of fibers (20).

18. Computer program product for carrying out the method according to one of claims 13 to 18.

19. Fiber bundle produced by the process according to any one of claims 13 to 18.

Images