DE102017105285A1 - Temperature sensor and associated manufacturing method - Google Patents

Abstract

The disclosure relates to a temperature sensor (100) comprising an optical waveguide (10) with at least one integrated temperature sensor element (11, 12), a capillary (20) at least partially surrounding the optical waveguide (10), typically a glass capillary, and a capillary (20). at least partially surrounding reinforcing layer (30). The disclosure further relates to a manufacturing method for a temperature sensor (100).

Description

TECHNICAL AREA

Embodiments of the disclosure relate to a temperature sensor with at least one integrated temperature sensor element. Further embodiments relate to a production method for a temperature sensor.

STATE OF THE ART

Temperature sensor elements integrated in optical waveguides for measuring a temperature or a temperature change are usually designed as interferometric elements, for example as a fiber Bragg grating. A light applied Bragg grating reflects z. B. a certain wavelength of light at a Bragg reflection wavelength. This Bragg reflection wavelength is dependent on the strain or compression of the optical waveguide in the region of the Bragg grating. In the case of a temperature sensor, the strain or compression is influenced by the thermal expansion of the optical waveguide in the region of the Bragg grating. In addition, the so-called thermo-optic effect affects the Bragg grating. By measuring the Bragg reflection wavelength, it is possible to draw conclusions about the temperature in the vicinity of the Bragg grating. The shift in the Bragg reflection wavelength caused by the change in the Bragg grating is thus a measure of the temperature or the temperature change.

In addition to a change in temperature, other mechanical loads, in particular those in the axial direction of the optical waveguide, cause a shift in the Bragg reflection wavelength. Also loads transverse to the axial direction can, for example, distort the measurement result of a temperature measurement. A temperature sensor with an optical waveguide, which has at least one integrated temperature sensor element, can be surrounded by a capillary at least in regions or accommodated in a capillary. The capillary protects the optical fiber and the integrated temperature sensor element from mechanical influences that are not related to a temperature change.

Conventional capillaries have mechanical disadvantages. For example, if a conventional capillary is subjected to a bending load, it breaks as soon as a critical load limit is exceeded.

SUMMARY OF THE REVELATION

It is an object of the present disclosure to specify a temperature sensor comprising an optical waveguide with at least one integrated temperature sensor element and a capillary surrounding the optical waveguide at least in regions, wherein the mechanical properties of the temperature sensor and / or the measurement accuracy are improved.

The present disclosure provides a temperature sensor according to claim 1. In addition, the present disclosure provides a mold according to claim 12. Further, the present disclosure provides a use of a temperature sensor according to claim 13. In addition, the disclosure provides a method of manufacturing a temperature sensor according to claim 15. Further developments emerge from the dependent claims.

According to one aspect, a temperature sensor comprises an optical waveguide with at least one integrated temperature sensor element; a capillary which at least partially surrounds the optical waveguide; and a reinforcing layer surrounding the capillary at least partially.

The mechanical properties of capillary materials without a surrounding reinforcing layer, in particular isotropic capillary materials such. As quartz glass or metal, are constant over the length of the capillary. In the temperature sensor described herein, a reinforcing layer is provided which surrounds the capillary at least in regions. The reinforcing layer can help to improve the mechanical properties such. B. to improve the rigidity of the temperature sensor. The stiffness includes z. B. the bending stiffness and / or the radial stiffness of the temperature sensor.

As a result, for example, a temperature sensor disclosed herein having a capillary with a reinforcing layer provided at least in some areas is less brittle than a conventional capillary, which may contribute to improving handling. For example, a temperature sensor disclosed here or its capillary with the reinforcing layer surrounding it at least in regions exhibits a progressive failure behavior in the event of an overload, for example a buckling load or bending load. The capillary will not fail abruptly, caused by a single mode of failure, but will show a combination of different modes. As a result, the capillary and thus the temperature sensor can be used better in a critical stress boundary.

According to a further aspect, a mold for producing a molded part, wherein the mold is made of a fiber composite material, comprises at least one of them disclosed temperature sensor, wherein the temperature sensor is integrated into the mold. Alternatively or additionally, according to the aspect, the mold for producing a molded part, wherein the mold is made of the fiber composite, at least one temperature sensor disclosed herein, wherein the temperature sensor is arranged on the mold.

In another aspect, a temperature sensor disclosed herein is used on a molding tool to produce a molding. The mold is made from a fiber composite material as used herein.

The formulation according to which the temperature sensor is used on the mold includes that the temperature sensor is used in the mold, for example, by integrating the temperature sensor into the mold. A use disclosed herein includes placing the temperature sensor on or in the mold and / or affixing the temperature sensor to or in the mold.

A temperature sensor provided on the molding tool or a temperature sensor integrated in the molding tool can measure a temperature on the surface of a molding made with the molding tool close to the surface of this molding. This can help to ensure fast and accurate measurement.

The mechanical properties of the capillary of the temperature sensor, which is provided on the mold or integrated into the mold, can be adapted to the behavior of the fiber composite material of the mold. In particular, the rigidity of the temperature sensor can be adjusted so that the handling and operation of the temperature sensor, which is integrated into the mold, are facilitated or improved.

According to a further aspect, a method for producing a temperature sensor comprises introducing a section of an optical waveguide with at least one integrated temperature sensor element into a capillary; surrounding the capillary at least in a region of the capillary with a reinforcing layer, wherein the reinforcing layer typically comprises wound or braided fibers; and closing, in particular strain relief and / or sealing, an axial end of the temperature sensor.

In embodiments, the reinforcing layer comprises wound or braided fibers. Examples of a fiber material for the wound or braided fibers are carbon fibers, aramid fibers or glass fibers. Typically, the fibers of the reinforcing layer comprise glass, aramid and / or carbon.

The fibers may be wound or braided in one or more layers. The more layers of fibers are wound or braided, the higher is usually the resulting stiffness of the temperature sensor. Among other things, by a suitable choice of the number of layers, the stiffness, in particular the bending stiffness, of the temperature sensor can be adapted to the local requirements.

The material for the fibers of the reinforcing layer may be selected according to a desired rigidity, in particular bending stiffness, of the temperature sensor. Carbon fibers have a higher stiffness than glass fibers under substantially the same conditions (especially fiber strength, wrap angle, wall thickness of the resulting reinforcing layer). Among other things, by a suitable choice of the fiber material, the stiffness, in particular the bending stiffness, of the temperature sensor can be adapted to the local requirements.

The choice of fibrous material for the fibers of the reinforcing layer may be made according to the properties of a target material. The measurement object material is the material that surrounds the temperature sensor in an arrangement or attachment in or on a measurement object or is applied to the temperature sensor. For example, the choice of material may be such that material properties of the fibers of the reinforcement layer are similar or the same to the associated material properties of the measurement object material. Examples of material properties are the electrochemical potential between the fiber material and the measurement object material and / or the thermal properties (in particular thermal expansion coefficient, thermal conductivity) of the fiber material with respect to the measurement object material.

Typically, the reinforcing layer comprises a fiber composite material. In a typical fiber composite for the reinforcing layer of a temperature sensor disclosed herein, the braided or wound fibers are surrounded by a matrix material. For example, the matrix material is a thermoset material such. B. an epoxide. The matrix material may also be a thermoplastic material.

The choice of the matrix material for the reinforcement layer can be made according to the properties of a measurement object material. The measuring object Material is the material that surrounds the temperature sensor in an arrangement or attachment in or on a measurement object or is applied to the temperature sensor. For example, the choice of material can be such that material properties of the matrix of the reinforcement layer are similar or the same to the associated material properties of the measurement object material. Examples of material properties are the electrochemical potential between the matrix material and the measurement object material and / or the thermal properties (in particular thermal expansion coefficient, thermal conductivity) of the matrix material with respect to the measurement object material.

Typically, in the use disclosed herein, a fibrous material in the fiber composite of the forming tool and a fibrous material of the reinforcing layer are the same. Alternatively or additionally, in embodiments of the use disclosed herein, a matrix material in the fiber composite of the mold and a matrix material of the reinforcing layer are the same.

For example, if the fibrous material in the fiber composite of the mold is carbon and the matrix material is an epoxy, carbon is typically also selected as the fibrous material of the reinforcing layer, and epoxy is also selected as the matrix material of the reinforcing layer. However, this is only an example, and the same applies to other fiber materials such. As glass or aramid and other matrix materials such. B. other thermoset or thermoplastic materials.

Such a choice of the respective materials can contribute to the thermal properties of the temperature sensor, in particular the capillary and the reinforcing layer, being similar or identical to those of the surrounding material of the molding tool. As a result, thermal stresses in the laminate of the materials can be reduced, which can contribute to reducing or avoiding damage by thermal stress, in particular cyclic thermal stress.

Such a choice of the respective materials may also help to reduce or avoid contact corrosion due to different electrochemical potentials between the temperature sensor and the surrounding material of the mold. Such corrosion deteriorates, for example, the mechanical properties such. As the laminate quality, but can thus be avoided.

The choice of the fiber material and / or the matrix material of the reinforcing layer can also be based on a desired thermal conductivity. For example, the thermal conductivity of a carbon fiber material is higher than that of a glass fiber material. A high thermal conductivity can cause a faster response of the at least one temperature sensor element in the temperature sensor.

In embodiments, the capillary has a glass capillary. Alternatively, in embodiments, the capillary has a plastic capillary. Alternatively, in embodiments, the capillary has a metal capillary. Alternatively, in embodiments, the capillary has a ceramic capillary.

In embodiments, the at least one integrated temperature sensor element comprises a fiber Bragg grating. A fiber Bragg grating makes it possible, via a measurement of the shift of its characteristic wavelength on the impact of measuring light, to draw conclusions about a compression or expansion of the fiber Bragg grating and / or a thermal influence on the fiber by the thermo-optical effect To determine -Bragg grid. Compression or stretching of the fiber Bragg grating may result from a temperature change. The determination of the compression or elongation and / or the determination of the thermal influence on the fiber Bragg grating, which results from the thermo-optic effect, via the measurement of the shift of the characteristic wavelength of the fiber Bragg grating, gives a measure of the temperature change.

Alternatively or additionally, in embodiments, the at least one integrated temperature sensor element has a backscatter element for a fiber optic backscatter measurement method. An example of a fiber optic backscatter measurement method that allows a conclusion to a temperature or a temperature change of the backscatter element is an optical frequency domain reflectometry method.

A backscatter element is, for example, a section (segment) of the optical waveguide which exhibits a characteristic scattering pattern for incident measuring light in the frequency domain. A characteristic scattering pattern is in the section, for example, due to an influence on the waveguide geometry of the optical waveguide, due to local defects such. B. impurities, modified refractive indices or the like. For example, a ground state for the characteristic scattering pattern of the portion or characteristic properties for the characteristic scattering pattern of the portion is determined in advance.

When there is a change in temperature of the backscatter element, that is to say of the section, the characteristic scatter pattern which can be determined in the backscatter measurement method is stretched or compressed over the frequency curve. The thermo-optic effect can also have an influence on the characteristic scattering pattern. The strain or the compression and / or influence by the thermo-optical effect can be determined in a suitable evaluation method, for example in a correlation measuring method, which relates the course of the changed characteristic scattering pattern to the ground state. A measure of the change allows a conclusion on the temperature change of the backfill element.

In embodiments, the optical waveguide includes a plurality of integrated temperature sensor elements spaced apart from one another in the direction of an axis of the optical waveguide. Typically, the optical fiber comprises two or three or more integrated temperature sensor elements.

In the case of different test objects, for example in the case of a mold made of a fiber composite material, a plurality of temperature individual sensor elements are conventionally used for temperature measurement, which use, for example, an electrical measuring method and / or are embedded in the mold. These individual sensors are individually electrically connected to a measuring system. With the temperature sensor disclosed herein, the optical waveguide of which comprises a plurality of integrated temperature sensor elements, it is possible, for example, to minimize the necessary circuitry for measuring the temperature by reducing the number of necessary test leads and / or the total length of the installed test leads. As a result, costs can be reduced and / or a negative effect on the mechanical properties of the test object can be reduced, which is caused by the integrated sensors with individual sensors and their electrical connection.

The various temperature sensor elements of the temperature sensor disclosed herein may have different optical characteristics to allow discrimination of the measurement signals. For example, when fiber Bragg gratings are used, the characteristic wavelengths of the individual fiber Bragg gratings may be different. If, alternatively or additionally, backscatter elements are used for a fiber optic backscatter measurement method, the characteristic scattering patterns of the individual backscatter elements may differ from one another.

Multiple temperature sensor elements in a single optical fiber may allow for measurement of the particular temperature or temperature change at different spatial locations. When a temperature sensor disclosed herein is placed or mounted on or within a measurement object, the respective temperatures may measure at different locations in or on the measurement object.

If several temperature sensor elements are present in the optical waveguide, a plurality of measurement signals can be determined during a measurement. An assignment of the individual measurement signals to the locations in or on the measurement object takes place, for example, via the known and / or previously determined different characteristics of the temperature sensor element. In the case of fiber Bragg gratings, the assignment takes place, for example, via the respective characteristic wavelength; Accordingly, the assignment takes place in backscatter elements for a fiber optic backscatter measurement method on the respective characteristic scatter pattern.

For example, the individual temperature sensor elements are spaced from each other by more than 3 cm or more than 5 cm or more than 10 cm. The distance between the individual temperature sensor elements, d. H. the spatial density of temperature sensor elements in the optical fiber does not need to be uniform. It can be provided, for example, to adapt the spatial density of the temperature sensor elements to an expected temperature distribution in a measurement object at or in which the temperature sensor is arranged or mounted. An example of an expected temperature distribution is the distribution of possible "hot spots" in a tool mold or the like.

A temperature sensor with a plurality of temperature sensor elements thus provides the possibility of temperature measurement at a plurality of measuring points, wherein the space requirement or Verschaltungsaufwand is reduced in comparison to the provision of multiple temperature sensors for the different measuring points.

In embodiments, the capillary has a wall thickness of less than 0.1 mm. Typically, the capillary has a wall thickness of less than 0.07 mm or less than 0.05 mm. The wall thickness, as used herein, is the thickness of the layer in question.

In embodiments, the reinforcing layer has a wall thickness of more than 0.1 mm. Typically, the reinforcing layer has a wall thickness of greater than 0.13 mm or greater than 0.15 mm.

In embodiments, the rigidity of the temperature sensor can be predetermined or predefined at least in regions by predetermining an orientation angle of the fibers of the reinforcement layer relative to a direction of an axis of the temperature sensor. Typically, the direction of the axis of the temperature sensor corresponds to the direction of the axis of the optical waveguide.

The orientation angle of the fibers typically corresponds to the winding angle of the fibers. A winding angle of 0 ° indicates a fiber profile, which is aligned in the direction of the axis of the temperature sensor or the optical waveguide. The closer the winding angle approaches an angle of 90 °, the more the fiber orientation approaches an orientation perpendicular to the direction of the axis of the temperature sensor or of the optical waveguide.

Depending on the orientation angle at which the fibers (the reinforcing fibers) of the reinforcing layer are applied to the capillary, the mechanical properties of the capillaries, in particular their stiffness, change. If the fibers are applied in an axial direction, the capillary becomes more rigid. If the fibers are applied in a more radial direction, the capillary becomes less sluggish and / or more pressure-resistant.

It is conceivable that the orientation angle of the fibers of the reinforcing layer in the overall extent of the reinforcing layer along the axis of the temperature sensor is substantially equal. In this case, a substantially constant rigidity of the temperature sensor is achieved.

However, the orientation angle of the fibers of the reinforcing layer may also be changed in the course of the reinforcing layer along the axis of the temperature sensor.

For example, the reinforcing layer may have different areas in the direction of the axis of the temperature sensor, wherein the orientation angle of the fibers of the reinforcing layer is the same within each of the different areas, but different from each other at least in two of the different areas. The regions of the reinforcing layer with the different orientation angles of the fibers can then have different stiffnesses.

It is also possible to continuously change the orientation angle of the fibers of the reinforcing layer to obtain a continuously variable rigidity of the temperature sensor. For example, it is possible to change the orientation angle of the fibers of the reinforcing layer in the current production process of a temperature sensor in order to achieve a stepless variation of the rigidity over the axial course.

It is possible to combine several winding angles of the fibers, for example in several layers of the fibers. In particular, it is possible to combine a winding angle of substantially 0 ° with a winding angle other than 0 °. Such a combination can be obtained, for example, in a pull-winding method. In a pull-winding process, the fibers are both extruded (or pulltruded) and wound. The fibers of the one layer are then aligned at a winding angle of 0 ° and oriented in the direction of the temperature sensor (in the capillary direction or in the direction of the optical waveguide). The fibers of another layer are then aligned at a winding angle different from 0 °. This winding angle of the other layer can also be changed continuously, for example, during the ongoing production process. As a result, depending on the application, an advantageous stiffness behavior can be achieved.

In embodiments, the orientation angle of the fibers of the reinforcing layer is set in a range of 20 ° to 80 ° to the axis of the temperature sensor. In the above combination of an orientation angle of 0 ° and an orientation angle different from 0 °, the position in which the orientation angle of the fibers of the reinforcing layer is other than 0 ° is set in a range of 20 ° to 80 ° according to the embodiment. A range of 20 ° from 80 ° is a typical process stable range.

For example, the orientation angle of the fibers of the reinforcing layer is set in a range of 20 ° to 40 °, and typically about 25 °. The orientation angle is selected, for example, depending on the number of filaments in the fiber bundle. With a relatively thick strand of fibers, it may be advantageous to choose a shallower angle to avoid overlapping of the fibers within the same winding layer of the reinforcing layer.

Certain mechanical properties of the temperature sensor are adjustable by the orientation angle of the fibers. As a result, the temperature sensor can also be applied, for example, to curved structures of a test object with tight bending radii. In addition, for example, the mechanical properties of the temperature sensor can be adjusted so that the sensor withstands high radial forces while remaining relatively flexible.

In embodiments, at least one axial end of the temperature sensor comprises a closure element.

The closure element typically includes a strain relief closure element. A strain relief closure member is provided at the axial end of the temperature sensor through which the optical fiber is guided. For example, the strain relief closure element is a resin material or an adhesive, and is typically connected to the axial end of the temperature sensor, such as the capillary, as well as the inserted optical fiber in the region of the axial end such that mechanical manipulations of the optical fiber in areas outside the Capillary have no or only minor effects on the at least one temperature sensor element.

The closure element alternatively or additionally comprises a sealing closure element. A sealing closure member is provided at the axial end of the temperature sensor, which is different from the axial end through which the optical waveguide is guided. Typically, the optical fiber is not routed to the sealing closure member to prevent mechanical stresses not due to a temperature change from being transmitted to the at least one temperature sensing element.

Both the strain relief closure element and the sealing closure element can perform a sealing function by protecting the interior of the capillary from the ingress of substances. Such substances may include solids, liquids and / or gases. In the use disclosed herein, such substances may be, for example, injection resins needed during the manufacture of a molded article in the mold.

list of figures

• 1 eine schematische Querschnitts-Seitenansicht eines Temperatursensors gemäß einer Ausführungsform;
• 2 eine schematische Draufsicht des Temperatursensors aus 1;
• 3 ein Diagramm, das einen schematischen Messaufbau zur Durchführung einer Temperaturmessung mit dem Temperatursensor gemäß einer Ausführungsform zeigt;
• 4 ein Ablaufdiagramm für ein Verfahren zum Herstellen eines Temperatursensors gemäß einer Ausführungsform.

Embodiments of the invention are illustrated in the drawings and explained in more detail in the following description. In the drawings show:

• 1 a schematic cross-sectional side view of a temperature sensor according to an embodiment;
• 2 a schematic plan view of the temperature sensor 1 ;
• 3 a diagram showing a schematic measurement structure for performing a temperature measurement with the temperature sensor according to an embodiment;
• 4 a flowchart for a method of manufacturing a temperature sensor according to an embodiment.

EMBODIMENTS OF THE DISCLOSURE

Hereinafter, embodiments will be explained in more detail. The drawings are illustrative of one or more examples of embodiments. Unless otherwise noted, the same or equivalent elements have the same reference numerals.

Embodiments described herein relate, inter alia, to a temperature sensor generally designated 100 and in cross-sectional side view of FIG 1 and in the plan view of 2 is shown schematically.

The temperature sensor 100 includes an optical fiber 10 , which at an axial end E1 into a capillary 20 is introduced. The optical fiber 10 In the embodiment shown, for example, comprises two temperature sensor elements 11 . 12 , which are each formed as a fiber Bragg grating. The fiber Bragg gratings are for example by means of a laser in the optical waveguide 10 enrolled. The disclosure is not limited to a number of two temperature sensor elements 11 . 12 , and in the optical waveguide 10, only one temperature sensor element or more than two temperature sensor elements 11 . 12 be educated. The temperature sensor elements are also not limited to fiber Bragg gratings, although the following exemplary description of the embodiment assumes fiber Bragg gratings.

The capillary 20 is in the embodiment of a glass capillary, but it can also be made of other suitable materials such. B. plastic or metal. The capillary 20 one has the capillary 20 At least partially surrounding reinforcing layer 30 on. The reinforcing layer is in the illustrated embodiment in the region of the entire capillary 20 but the disclosure is not limited thereto. The reinforcing layer 30 is preferably with the capillary 20 inseparably connected.

In the illustrated embodiment, the reinforcing layer 30 wound fibers, which are surrounded as a fiber composite material of a matrix, for example of epoxy. The fibers may for example be selected from carbon, glass fibers, basalt fibers, natural fibers and / or aramid fibers. How out 2 As can be seen, in the exemplary embodiment, the fibers are at a homogeneous wrap angle α around the capillary 20 wound, which is approximately 70 ° in the representation. The winding angle α is not limited to this value exemplified and shown. In particular, in the case of a comparatively thick bundle of fibers, the winding angle can also be chosen to be significantly lower, for example at about 25 °. Through the reinforcement layer 30 is the capillary 20 less brittle than a comparable, for example made of quartz glass capillary without reinforcing layer.

The optical fiber 10 is thus in an area of the capillary 20 and the reinforcing layer 30 surrounded or enveloped and is thereby decoupled from mechanical influences, such as mechanical strains or mechanical bending influences. The decoupling can contribute to the measurement accuracy for the temperature measurement by means of the temperature sensor elements 11 . 12 to improve.

The optical fiber 10 is at an axial end E1 of the temperature sensor 100 at which he enters the capillary 20 which is inserted with a closure element 41 strain relief. The closure element 41 is formed for example of an adhesive or a resin and can - in addition to the strain relief - also seal the axial end E1. In addition, at the other axial end E2 of the temperature sensor 100 a closure element 42 provided which seals the axial end E2.

The optical fiber 10 reaches into the capillary 20 however, in the embodiment, it is only at the one axial end E1 by means of the closure element 41 stored. The optical fiber 10 and thus its temperature sensor elements 11 . 12 are therefore one-sided. As a result, it is possible to prevent the mechanical loads acting on the temperature sensor 100, which differ from a temperature-induced change, from occurring on the optical waveguide 10 be transmitted. If the capillary is stretched or compressed to an extent that corresponds to a design value, this will have no or negligible effect on the temperature measurement signal.

The closure elements 41 . 42 In addition, ensure that no foreign substances enter the capillary 20 penetration. An impurity can be especially if the temperature sensor 100 used for temperature measurement on a fiber composite molding tool, an injection resin or the like containing the temperature sensing elements 11 . 12 would make us unusable.

3 schematically shows the temperature sensor 100 out 1 or 2 who is in a measuring object 200 is integrated. The measurement object 200 is for example a mold for producing a molded part. The mold is z. B. formed of a fiber composite material, for example of a fiber composite plastic. The molded part to be produced with the molding tool can, for example, likewise be formed from a fiber composite material, for example from a fiber composite plastic. The disclosure is not limited to that of the temperature sensor 100 into the measurement object 200 integrated, and the temperature sensor 100 can only partially into the measurement object 200 be integrated or arranged on the surface.

The material for the fibers and the matrix material of the reinforcing layer 30 of the temperature sensor 100 are in the embodiment, respectively, the same as the respective materials of the mold 200 , This allows thermal stresses between the temperature sensor 100 and the mold 200 kept small or avoided. In addition, the electrochemical potential between the temperature sensor 100 and the mold 200 same, which may contribute to reducing or eliminating contact corrosion.

The from the mold 200 led out optical fiber 100 is to a beam splitter 110 guided. Behind the beam splitter, the optical fiber 10 preferably with broadband measuring light from a measuring light source 120 be applied to the temperature sensor elements 11 . 12 of the optical waveguide is guided and is reflected there wavelength-dependent. Returning measuring light can after passing through the beam splitter 110 with a possibly wavelength-sensitive photosensor 130 be detected. A measurement control 140 controls the measuring light source 120 and the photosensor 130 accordingly and evaluates the signals from the photosensor 130 out.

When the temperature changes, the temperature sensor elements become 11 . 12 in the optical fiber 10 mechanically stretched or compressed. The thermo-optic effect also has an effect on the behavior of the temperature sensor elements 11 . 12 , The thermo-optic effect can have a stronger influence on the behavior of the temperature sensor elements 11 . 12 as an elongation or compression, for example a ten times stronger effect. A Bragg reflection wavelength of the temperature sensor elements formed as fiber Bragg gratings 11 . 12 is a measure of the temperature change ΔT: $$\frac{\mathrm{\Delta }\lambda }{\lambda }=k\cdot \mathrm{\Delta }T$$

The constant k depends on the material of the optical waveguide.

The characteristic wavelengths of the temperature sensor elements formed in the embodiment as a fiber Bragg grating 11 . 12 differ from each other. This makes it possible, the measurement signals of the individual temperature sensor elements 11 . 12 to distinguish from each other.

The temperature sensor elements 11 . 12 are located at different locations, ie along the axis A of the optical waveguide 10 spaced from each other. For a known position of the temperature sensor elements 11 . 12 It is possible, the respective different temperatures at the relevant (assigned) position on the measurement object 200 separated and determined in a single measurement.

4 shows a flowchart of a method for manufacturing a temperature sensor 100 ,

First, in a first operation 1001 a portion of an optical waveguide 10 having at least one integrated temperature sensor element 11 . 12 has, in a capillary 20 brought in.

In a subsequent process 1002 becomes the capillary 20 at least in one area 20 the capillary 20 with a reinforcing layer 30 surround. The reinforcing layer 30 typically has wound or braided fibers. Typically, the fibers form the reinforcing layer 30 with a matrix material a fiber composite material.

The processes 1001 and 1002 can also be done in reverse order.

In a subsequent process 1003 becomes an axial end E1, E2 of the temperature sensor 100 closed, in particular strain relieved. Typically, that axial end E1 of the temperature sensor 100 closed and strain relieved, through which the end of the optical waveguide 10 introduced into the capillary. The process ends with it.

Although the embodiments of the present invention have been described above by means of typical embodiments, it is not limited thereto, but modifiable in many ways. Also, the invention is not limited to the applications mentioned.

Claims (15)

Temperature sensor (100) comprising: an optical waveguide (10) having at least one integrated temperature sensor element (11, 12); a capillary (20) surrounding the optical waveguide (10) at least in regions; a reinforcing layer (30) surrounding the capillaries (20) at least in regions. Temperature sensor (100) after Claim 1 wherein the reinforcing layer (30) comprises wound or braided fibers. Temperature sensor according to one of the preceding claims, wherein the capillary (20) comprises a glass capillary, a plastic capillary, a ceramic capillary or a metal capillary. Temperature sensor (100) according to one of the preceding claims, wherein the at least one integrated temperature sensor element (11, 12) comprises a fiber Bragg grating and / or a backscatter element for a fiber optic Rückstreumessverfahren. Temperature sensor (100) according to one of the preceding claims, wherein the optical waveguide (10) comprises a plurality of integrated temperature sensor elements (11, 12), typically two or three or more integrated temperature sensor elements, wherein the individual temperature sensor elements (11, 12) from each other in the direction an axis (A) of the optical waveguide are spaced. A temperature sensor (100) according to any one of the preceding claims, wherein the capillary (20) has a wall thickness of less than 0.1 mm, typically less than 0.07 mm or less than 0.05 mm. A temperature sensor (100) according to any one of the preceding claims, wherein the reinforcing layer (30) has a wall thickness of greater than 0.1 mm, typically greater than 0.13 mm or greater than 0.15 mm. Temperature sensor (100) according to one of Claims 2 to 7 wherein the fibers of the reinforcing layer (30) comprise glass, aramid, basalt fibers, natural fibers and / or carbon. Temperature sensor (100) according to one of Claims 2 to 8th wherein the rigidity of the temperature sensor (100) can be predetermined at least in regions by predetermining an orientation angle of the fibers of the reinforcement layer (30) relative to a direction of an axis of the temperature sensor (100). Temperature sensor after Claim 9 wherein the orientation angle of the fibers of the reinforcing layer (30) is set in a range of 20 ° to 80 °, typically in a range of 20 ° to 40 ° or at approximately 25 °, to the axis of the temperature sensor (100). Temperature sensor (100) according to one of the preceding claims, wherein at least one axial end (E1, E2) of the temperature sensor comprises a closure element (41, 42), typically a strain relief closure element and / or a sealing closure element. Mold (200) for producing a molded part, wherein the mold (200) is made of a fiber composite material and at least one arranged on the mold and / or at least one integrated into the mold temperature sensor (100) according to one of Claims 1 to 11 includes. Use of a temperature sensor (100) according to one of Claims 1 to 11 on a molding tool (200) for producing a molded part, wherein the molding tool (200) is made of a fiber composite material. Use after Claim 13 wherein a fiber material in the fiber composite of the forming tool (200) and a fiber material of the reinforcing layer (30) of the temperature sensor (100) are the same, and / or wherein a matrix material in the fiber composite of the forming tool (200) and a matrix material of the reinforcing layer (30) of the temperature sensor (100) are the same. A method of manufacturing a temperature sensor (100), comprising: Introducing a section of an optical waveguide (10) with at least one integrated temperature sensor element (11, 12) into a capillary (20); Surrounding the capillary (20) at least in a region of the capillary (20) with a reinforcing layer (30), the reinforcing layer typically comprising wound or braided fibers; Closing, in particular strain relief and / or sealing, an axial end (E1, E2) of the temperature sensor (100).

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