DE102015224064A1 - Light-guiding device and method for operating a light-guiding device - Google Patents

Abstract

The invention relates to a light-conducting device (100) for directing a light beam (110) onto a measuring unit for measuring a substance or gas concentration. The light guide device (100) comprises a light guide unit (102) having a coupling-in section (104) for coupling the light beam (110) and a coupling-out section (106) for coupling the light beam (110) into a beam path to the measuring unit. Furthermore, it comprises a light receiving unit (108) which is designed to detect a portion (112) of the light beam (110) passing by the light guide unit (102) when emitting the light beam (110) and / or a light beam (110). between the coupling portion (104) and the decoupling portion (106) coupled-out transmission component (114) of the light beam (110) to detect and / or forward.

Description

State of the art

The invention is based on a device or a method according to the preamble of the independent claims. The subject of the present invention is also a computer program.

Exhaust gases can be detected, for example, by means of absorption spectroscopy in the UV range. For this purpose, the light can be shared by LEDs, wherein a part can be guided to a reference detector and another part, such as a glass fiber, to a measuring cell in an exhaust line.

Disclosure of the invention

Against this background, with the approach presented here, a light-guiding device for directing a light beam onto a measuring unit for measuring a gas concentration, a method for operating such a light-guiding device, furthermore a control unit which uses this method, and finally a corresponding computer program according to the main claims are presented. The measures listed in the dependent claims advantageous refinements and improvements of the independent claim device are possible.

A light-guiding device for guiding a light beam to a measuring unit for measuring a substance or gas concentration is presented, wherein the light-guiding device has the following features:
a light guide unit having a coupling-in section for coupling the light beam and a coupling-out section for coupling the light beam into a beam path to the measuring unit; and
a light-receiving unit which is designed to detect and / or forward a portion of the light beam passing by the light-guiding unit when the light beam is emitted and / or a transmission component of the light beam coupled out between the coupling-in portion and the coupling-out portion when the light beam is conducted.

By a measuring unit, for example, a measuring cell, a measuring detector or a reference detector can be understood. A light-guiding unit may, for example, be understood to mean a lens or a light guide, for example a planar light guide or a fiber optic cable. The coupling-in section or the coupling-out section can each be a cross-sectional area of one end of the light-guiding unit. For example, a detector unit, for example a photodetector, for detecting the passing component or coupled-out transmission component or a further light-guiding unit connected to the light-guiding unit, can be understood to be a forwarding unit or a coupled-out transmission component, for example a reference detector. For example, the light receiving unit may be configured to receive portions of the light beam that are transmitted or coupled out between the input and output coupling sections through a lateral surface of the light guide unit.

The light-guiding device is suitable, for example, for use in absorption spectroscopy, in particular for reference measurements in UV absorption spectroscopy for the optical detection of (off) gases such as nitrogen oxides (NO, NO ₂ ), sulfur oxides (SO ₂ ), ammonia (NH ₃ ) or ozone (O ₃ ).

The approach described here is based on the knowledge that it is possible to absorb and use light losses which occur when a light beam passes through a light guide device, for example to perform a reference measurement for determining a reference intensity. The light losses can occur, for example, when coupling and sharing the light. The approach described here has the advantage that already lost light can be exploited in the coupling from a light source into a light guide and / or from a light guide into another light guide in order to increase the system efficiency.

When transmitting light from one optical component to another optical component, light losses can occur. This may be the case, for example, when coupling light from light sources into a light guide, such as glass fibers or waveguides, or when transmitting from one light guide to another light guide, such as between glass fibers and waveguides. The light losses may be caused for example by (Fresnel) reflections at interfaces, by alignment errors of the optical components to each other, such as displacement or tilting, by defective surfaces of facets, by differently sized facet surfaces of different components or by different acceptance angles.

The light losses can be reduced, for example, by introducing an index matching gel between the components to reduce light losses by light reflections, by active alignment to reduce light losses due to alignment errors, or by surface treatment of the facets, such as by polishing.

The maximum coupling efficiency can be achieved by different areas and acceptance angle of the coupling-out element over the einkoppelnden element be limited. This is due to the fact that optical fibers can only pick up and guide light beams lying within the acceptance angle of the light guide. Light rays that are outside the acceptance angle can indeed enter the light guide, but are not guided there.

Thus, for example, light rays are totally reflected within the acceptance angle at the interface from the conductor core to the conductor jacket, whereas in the case of light rays outside the acceptance angle, the total reflection does not occur, but the Fresnel reflection. In this case, according to Fresnel's formulas, only a certain proportion of the light output is reflected, while the remainder, ignoring absorption, enters the conductor jacket and is thus lost for the desired light conduction in the conductor core.

In particular, when coupling light from light sources having a broad emission characteristic, such as light-emitting diodes, gas discharge lamps or thermal radiators, in light guides with acceptance angles of typically less than 20 degrees, such as glass fibers, the coupling efficiency may be less than 20 percent.

In various applications, it may be necessary to track the optical power of the light source during operation. For example, in the case of absorption spectroscopy, a light beam emanating from the light source can be divided such that a part of the light beam strikes a reference detector and a further part of the light beam is directed into a measuring cell. Thus, fluctuations of the light power generated by the light source can be determined before the measuring cell, which can be avoided that the fluctuations are mistakenly interpreted as a measurement signal. Such power fluctuations can be eliminated by a reference measurement.

In such a division of light losses may be incurred, on the one hand by the division itself, in which a certain proportion is required for the reference measurement, on the other hand by losses on the divider, for example because of the change in direction of the main or secondary beam, the conditions for total reflection in the Change light guide.

Such light dividers can be, for example, semipermeable mirrors, also called splitter mirrors, or beam splitter cubes. In the integrated optics, d. H. In waveguide systems, the light splitting can be realized by dividing the light-guiding structure into two or more light guides.

The approach presented here now allows a virtually loss-free splitting off of light at transitions between optical components by utilizing light beams which do not contribute to the further system function, for example to the light pipe. For example, the approach presented here enables almost loss-free splitting off of light for use on reference detectors.

For this purpose, for example, a secondary optical component such as the light receiving unit, such as a light guide or photodetector, are mounted at a transition point between a first and a second primary optical component, wherein the acceptance or radiation angle of the first primary component may be greater than the acceptance angle of the second primary component or a radiating surface of the first primary component may be larger than a receiving surface of the second primary component. The first primary component may be, for example, a light source or a light guide. The second primary component may be, for example, an optical fiber. Due to the smaller acceptance angle of the second primary component compared to the first primary component, a certain amount of light is not held in the light guide, but decoupled. Likewise, a certain amount of light may pass the second primary component. By appropriate placement of the secondary component, this light can be used, for example to perform a reference measurement. By means of such a high-efficiency optical light divider losses of optical interfaces can be minimized.

Another advantage lies in the compact and inexpensive construction of the light guide device, since additional light-dividing elements, such as a branching branch or a beam splitter, can be omitted.

According to one embodiment, the light receiving unit can be arranged on the light guide unit. Thereby, the light receiving unit can be arranged as close to the light guide unit, whereby a compact design of the light guide is made possible and light losses can be avoided when receiving the passing share or decoupled transmission component by the light receiving unit.

It is advantageous if the light receiving unit is arranged adjacent to the coupling-in section. As a result, the portion of the light beam passing through the coupling-in section or the transmission component, which is typically decoupled in the region of the coupling-in section, can be picked up by the light-receiving unit.

The light-guiding device may, according to a further embodiment, have a emitting unit for emitting the light beam. The emitting unit can be arranged facing the coupling-in section. Additionally or alternatively, the emitting unit may also be arranged opposite the light receiving unit. By a emitting unit, for example, a light source, a light guide or a lens can be understood. By means of the emitting unit, the light beam can be directed to the light receiving unit or the light guide unit.

It is advantageous if the emitting unit is arranged on the coupling-in section. As a result, light losses when coupling the light beam into the light guide unit can be kept as low as possible. In particular, the emitting unit by means of butt coupling with the light guide unit or in the case of a spatial distance between emitting unit and light guide unit via a suitable material, for. As an index matching adhesive connected.

Furthermore, the light guide unit can be realized as a light guide having a core and a jacket surrounding the core with a smaller refractive index than the core. The light receiving unit may be at least partially disposed on the shell and formed to receive the transmission component through the jacket. The core may, for example, be glass fibers or another light-conducting material having a greater refractive index than the cladding. By this embodiment, the light beam can be directed by total reflection from input to outcoupling. The arrangement of the light receiving unit on the jacket of the light guide unit, the light guide can be easily manufactured and designed to save space.

According to a further embodiment, a partial section of the light-receiving unit can project beyond an end of the light-guiding unit which encompasses the coupling-in section. In this case, the coupling-in section can be formed, for example, by a cross-sectional area of the end. By this embodiment, the largest possible portion of the light beam can be absorbed by the light receiving unit. In this case, for example, the emitting unit can be arranged both opposite to the projecting beyond the end of the light guide unit section and the coupling section.

Depending on the embodiment, the light-receiving unit can be realized as a photodetector, light guide or lens or a combination of photodetector, light guide or lens. This makes possible an efficient detection or transmission of the component or coupled-out transmission component passing by the light unit.

Furthermore, it is advantageous if the light receiving unit is designed to be annular or rectangular or frame-like. For example, the light receiving unit may extend annularly around the light guide unit. Thereby, the efficiency of the light-receiving unit can be increased.

The light-guiding device may further comprise a cover element for covering at least part of the light-receiving unit in an opaque manner. This allows a controlled illumination of the light receiving unit.

According to a further embodiment, the light-guiding device can have at least one further light-guiding unit with a further coupling-in section for coupling in a further light beam and a further coupling-out section for decoupling the further light beam into a beam path to the measuring unit and / or to another measuring unit for measuring a substance or gas concentration and at least have another light receiving unit. The further light receiving unit can be designed to detect a portion of the further light beam passing by the further light guide unit when the further light beam is emitted and / or a transmission component of the further light beam coupled out between the further coupling section and the further coupling section when the further light beam is conducted and / or forward. By this embodiment, the efficiency of the light guide can be increased.

The approach described here furthermore provides a method for operating a light-conducting device according to one of the preceding embodiments, the method comprising the following steps:
Reading in an intensity of the component passing by the light guide unit and / or an intensity of the transmission component;
Receiving a measurement signal provided by the measurement unit;
Determining a reference intensity using the intensity of the portion passing the light guide unit and / or the intensity of the transmission portion; and
Determining a mass or gas concentration using the reference intensity and the measurement signal.

As a result of this method, the proportion or transmission component received by the light-receiving unit that passes by the light-guiding unit can be used to perform a reference measurement, for example in the context of absorption spectroscopy for exhaust gas measurement.

This method can be implemented, for example, in software or hardware or in a mixed form of software and hardware, for example in a control unit.

The approach presented here also creates a control unit which is designed to execute, to control or to implement the steps of a variant of a method presented here in corresponding devices. Also by this embodiment of the invention in the form of a control device, the object underlying the invention can be achieved quickly and efficiently.

For this purpose, the control unit can have at least one arithmetic unit for processing signals or data, at least one memory unit for storing signals or data, at least one interface to a sensor or an actuator for reading sensor signals from the sensor or for outputting control signals to the actuator and / or or at least a communication interface for reading or outputting data embedded in a communication protocol. The arithmetic unit may be, for example, a signal processor, a microcontroller or the like, wherein the memory unit may be a flash memory, an EPROM or a magnetic memory unit. The communication interface can be designed to read or output data wirelessly and / or by line, wherein a communication interface that can read or output line-bound data, for example, electrically or optically read this data from a corresponding data transmission line or output to a corresponding data transmission line.

In the present case, a control device can be understood as meaning an electrical device which processes sensor signals and outputs control and / or data signals in dependence thereon. The control unit may have an interface, which may be formed in hardware and / or software. In the case of a hardware-based embodiment, the interfaces can be part of a so-called system ASIC, for example, which contains various functions of the control unit. However, it is also possible that the interfaces are their own integrated circuits or at least partially consist of discrete components. In a software training, the interfaces may be software modules that are present, for example, on a microcontroller in addition to other software modules.

The sensor signals may, for example, be signals of a sensor of a motor vehicle or of sensors installed in a motor vehicle. The sensor signals may thus be signals of a gas sensor, for example a lambda probe, a pressure sensor, which is installed, for example, in a bumper, or an acceleration sensor, for example an ESP sensor. The control and / or data signals may be signals sent to a control unit, such as a brake or engine control unit. On the basis of these signals, the control unit can then decide whether, for example, a warning signal is output during a malfunction of the tested sensor and / or an emergency program is activated which activates certain units, such as brake actuators in the motor vehicle, and / or certain units of the motor vehicle are deactivated to bring about a safe operating state.

Also of advantage is a computer program product or computer program with program code which can be stored on a machine-readable carrier or storage medium such as a semiconductor memory, a hard disk memory or an optical memory and for carrying out, implementing and / or controlling the steps of the method according to one of the embodiments described above is used, especially when the program product or program is executed on a computer or a device.

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

1 a schematic representation of a light guide device according to an embodiment;

2 a schematic representation of a light guide device according to an embodiment;

3 a schematic representation of a light guide device according to an embodiment;

4 a schematic representation of a light guide device according to an embodiment;

5 a schematic representation of a light guide device according to an embodiment;

6 a schematic representation of a light guide device according to an embodiment;

7 a schematic representation of a light guide device according to an embodiment;

8th a schematic representation of a light guide device according to an embodiment;

9 a schematic representation of a light guide device according to an embodiment;

10 a schematic representation of a beam path through a light guide unit according to an embodiment;

11 a flowchart of a method for operating a light guide device according to an embodiment; and

12 a block diagram of a control device according to an embodiment.

In the following description of favorable embodiments of the present invention, the same or similar reference numerals are used for the elements shown in the various figures and similar acting, with a repeated description of these elements is omitted.

1 shows a schematic representation of a light-guiding device 100 according to an embodiment. The light-guiding device 100 includes a light guide unit 102 with a coupling section 104 and a decoupling section 106 and a light receiving unit 108 , The light guide unit 102 is adapted to one on the coupling section 104 incident light beam 110 to the decoupling section 106 to conduct, with the light beam 110 at the decoupling section 106 from the light guide unit 102 is decoupled. The light receiving unit 108 is trained to take a share 112 of the light beam 110 when irradiating the light guide unit 102 with the light beam 110 at the light guide unit 102 passes by, record. Further, the light-receiving unit 108 formed to one between the coupling section 104 and the decoupling section 106 , for example through a lateral surface of the light guide unit 102 , transmitted transmission component 114 of the light beam 110 take. The light receiving unit 108 is realized, for example, as a photodetector to an intensity of the at the light guide unit 102 passing share 112 or the transmission component 114 to eat. Alternatively, the light receiving unit 108 realized as a light guide to the at the light guide unit 102 passing share 112 or the transmission component 114 in one of a light-guiding direction of the light-guiding unit 110 forward divergent direction.

According to this embodiment, the light guiding device 100 with a sending unit 116 to send out the light beam 110 executed, such as a light emitting diode, a lens or a light guide. An example is the sending unit 116 according to 1 the coupling section 104 here by a cross-sectional area of one end of the light guide unit 102 is formed, arranged opposite one another. Here, the sending unit 116 a large radiating cone with a large beam angle 118 on while the coupling section 104 a small acceptance cone with a small acceptance angle 120 having.

In 1 is the basic principle of the light guide 100 , also called light divider, shown. Light rays due to different emission or acceptance angle of the emitting unit 116 , also called first primary component, and the light guide unit 102 , also called second primary component, not in the light guide unit 102 can be performed in the light receiving unit 108 , also called secondary component, used.

This is light from the emission unit 116 in the light guide unit 102 transfer. The acceptance or emission angle of the emission unit 116 is greater than the acceptance angle of the light guide unit 102 , Light rays outside the acceptance angle of the light guide unit 102 arrive, are decoupled from this. The light receiving unit 108 is radially offset from the optical axis of the light guide 100 arranged and receives those light rays, which the light guide unit 102 can not accommodate due to the limited acceptance angle.

As in 1 to recognize, is in the light guide 100 no light is diverted from the actual system at an interface between two optical components with different acceptance angles, but instead uses loss radiation, ie light which is lost at the interface due to radiation outside the acceptance angle.

In particular, when coupling light from a light emitting diode in a light guide physically only a small proportion of light can be coupled into the light guide. For example, the theoretical maximum coupling-in efficiency η of a light-emitting diode with Lambertian radiation behavior, emitting surface A _LED = 200 × 200 μm ² , is calculated in a light guide, here glass fibers with a core diameter of 62.5 μm, with an area of the conductor _core of A _core π (62.5 μm) ^2/4 = 3068 μm ² and a numerical aperture NA = 0.3 in air as medium with an approximated refractive index of n _medium = 1 M. Hudson, Calculation of the Maximum Optical Coupling Efficiency into Multimode Optical Waveguides, Applied Optics Vol. 5, 1974, pp. 1029-1033 , as follows:

Instead of extracting additional light for this coupled-in light component for light divisions, for example for a reference measurement, by means of the light-guiding device 100 Proportions of light lost from the LED when coupled in may be used to make the reference measurement.

Depending on the embodiment, the sending unit 116 realized as a light source, in particular as a light emitting diode, optical fiber, such as glass fiber or waveguide, or lens. The light guide unit 102 is realized for example as a light guide or lens. In the light-receiving unit 108 Depending on the exemplary embodiment, this is a photodetector, a light guide or a lens.

The sending unit 116 and the light guide unit 102 may be placed in direct contact with each other, such as by butt coupling, or also separated by a medium such as air, an index matching optical adhesive or immersion oil.

2 shows a schematic representation of a light-guiding device 100 according to an embodiment. In the light guide 100 For example, it is one based on 1 described light guide. According to this embodiment, the light guide unit 102 as a light guide with a core 200 and one the core 200 surrounding coat 202 realized, with the coat 202 a smaller refractive index than the core 200 having. This allows the light beam 110 by total reflection in the light guide unit 102 to get redirected.

The light receiving unit 108 , here a photodetector, is adjacent to the coupling section 104 on the coat 202 the light guide unit 102 arranged. Thus, the light-receiving unit 108 trained to the transmission component 114 through the coat 202 through to detect. To prevent the at the light guide unit 102 passing share 112 on the at the coupling section 104 placed light receiving unit 108 is one of the sending unit 116 facing portion of the light receiving unit 108 through a cover 204 , here a panel, opaque covered. The cover element 204 prevents light directly from the sending unit 116 on the light receiving unit 108 meets, so only the light guide unit 102 through the coat 202 emerging light is recorded. Such an arrangement may, for example, be used to detect possible changes in the light coupling into the light guide unit 102 , z. B. due to aging or pollution effects on Einkoppelabschnitt 104 , via the light receiving unit 108 detect in the form of a reference detector.

3 shows a schematic representation of a light-guiding device 100 according to an embodiment. In contrast to 2 is the sending unit 110 according to 3 both the coupling section 104 as well as the light receiving unit 108 arranged opposite, wherein the light receiving unit 108 realized without the cover. By this arrangement it is achieved that the light receiving unit 108 both at the light guide unit 102 passing share 112 as well as the transmission rate 114 ie, the light receiving unit 108 measures both light directly from the sending unit 116 comes, as well as light coming out of the light unit 102 comes. Because in this case the sending unit 116 larger than the light guide unit 102 is dimensioned, even rays that are actually within the acceptance angle, ie relatively horizontally, reach the light receiving unit 108 ,

Especially with a spatial separation between the sending unit 116 and the light guide unit 102 can by a different dimensioning of the sending unit 116 and the light guide unit 102 as they are in 3 is shown that even light rays, although within the acceptance angle of the light guide unit 102 lie, but not on the coupling section 104 meet as they are at the light guide unit 102 pass by, at the light receiving unit 108 be caught.

According to another embodiment, a combination of the in the 2 and 3 shown embodiments are realized. These can be two or more light receiving units 108 on and / or around the light guide unit 102 be arranged around, wherein both embodiments with cover 204 , as in 2 shown as well as without, as in 3 shown to be used. As a result, on the one hand to light receiving units 108 without cover element 204 both a combination of the at the light guide unit 102 passing light component 112 as well as the transmission component 114 , On the other hand via a light receiving unit 108 with cover element 204 only the transmission component 114 , From this information, the at the light guide unit 102 passing light component 112 be calculated.

According to a further embodiment, the in 2 shown cover 204 between the light receiving unit 108 and the light guide unit 102 be arranged, for example by depositing an absorbent layer on the light guide unit 102 , As a result, the transmission component reaches 114 not on or in the Light-receiving unit 108 and only the light guide unit reaches it 102 passing share 112 in the light receiving unit 108 , By this arrangement, the light receiving unit 108 Favorable immediately and only via a cover 204 separated, at the light guide unit 102 be arranged without the light receiving unit 108 the transmission component 114 receives.

4 shows a schematic representation of a light-guiding device 100 according to an embodiment. In contrast to 3 is the light-receiving unit 108 according to this embodiment, outside the light guide unit 102 the sending unit 116 arranged opposite. The light receiving unit 108 is arranged such that only the at the light guide unit 102 passing share 112 on the light receiving unit 108 falls and the transmission rate 114 at the light receiving unit 108 is bypassed.

By such placement of the light receiving unit 108 can be collected rays due to different dimensions of the primary components or by strong side-emitting radiation from the emitting unit 116 not on the light guide unit 102 to meet. By placement in front of the light guide unit 102 Only rays are collected directly from the sending unit 116 come.

5 shows a schematic representation of a light guide unit 100 according to an embodiment. In the 5 shown light guide 100 is essentially the same as in 4 shown light guide, with the difference that the light receiving unit 108 here on the coat like this 202 attached is that a section 500 the light receiving unit 108 over the coupling section 104 protrudes. Here stands the subsection 500 so far beyond the coupling section 104 in addition, that opposite to the coupling section 104 placed sending unit 116 from the subsection 500 is covered. This has the effect of being on the light guide unit 102 passing share 112 on the over the coupling section 104 protruding section 500 meets while the transmission component 114 on one on the coat 202 attached further section 502 the light receiving unit 108 meets.

According to one embodiment, the light receiving unit 108 formed as a long detector to both direct radiation from the emitting unit 116 as well as radiation from the light guide unit 102 to eat. By reading out the corresponding detector lines, it is possible, for example, to read out the light components separately from one another and thus for aging effects on the emitting unit 116 or the light guide unit 102 draw conclusions.

Will the light receiving unit 108 sufficiently long and, as in 5 shown over the cut surface of the light guide unit 102 placed away, so the light receiving unit 108 both rays that are not on the light guide unit 102 meet, as well as rays that are not in the light guide unit 102 guided and uncoupled field. When using a photodetector as a light receiving unit 108 it is possible in such an arrangement via local readout of the detector surface, between a directly from the emitting unit 116 coming light power and one from the light guide unit 102 differing light output. This can both aging effects of the emission unit 116 as well as aging effects on an entrance surface of the light guide unit 102 captured and used for referencing.

By using an opaque cover member, such as an absorber, reflector or aperture, it is possible to use the light receiving unit 108 at least partially cover so that, for example, only rays from the emitting unit 116 or only beams from the light guide unit 102 on the light receiving unit 108 as previously described with reference to 2 is described.

6 shows a schematic representation of a light-guiding device 100 according to an embodiment. The light-guiding device 100 is essentially the same as in 2 shown light guide, with the difference that the light guide device 100 in 6 realized without the cover. Shown is the coupling of light from the emission unit 116 in the light guide unit 102 using the non-couplable light using the light-receiving unit 108 ,

7 shows a schematic representation of a light-guiding device 100 according to an embodiment. In contrast to the above with reference to the 2 to 6 described light guide is the in 7 shown light guide 100 with one to the light guide unit 102 connected secondary light guide as a light receiving unit 108 realized. This allows the light without additional losses in two conductors, ie the light guide unit 102 and the light receiving unit 108 , be split.

8th shows a schematic representation of a light-guiding device 100 according to an embodiment. In contrast to a preceding on the basis of 2 to 7 described light-guiding device is the light-guiding device 100 according to 8th by way of example with two further light-conducting units 800 each with a further coupling section for Coupling a further light beam and each realized a further coupling-out for coupling out the further light beam. At the other light-guiding units 800 is ever another light receiving unit 802 arranged. The other light receiving units 802 are analogous to the light receiving unit 108 designed to detect the respective scattering or transmission components of the further light beams.

The light-conducting units 102 . 800 are according to one embodiment as a planar light guide with sheath 200 and core 202 realized.

In the 8th shown light guide 100 is exemplary with three emission units 116 implemented in the form of glass fibers, each with a transmitting unit 116 depending on a coupling-in section of the light-guiding units 102 . 800 is arranged opposite.

According to one embodiment, the light guide units 102 . 800 and the sending units 116 on a common carrier layer 804 arranged. Here, the light receiving units 108 . 802 at least in sections in the carrier layer 804 be integrated.

Possible detector positions are exemplified above, below and laterally of the light guide units 102 . 800 located.

Depending on the exemplary embodiment, the light-receiving units are placed in direct contact or at a distance from the emitting units or light-guiding units.

Here, the light receiving units are placed, for example, on, under or next to a planar light guide as a light unit. It is also conceivable that a plurality of light receiving units are mounted on a light guide unit.

Depending on the embodiment, the light receiving units are shaped so that they have contact on several sides with their respective light guide unit. As a result, more light beams can be recorded. For example, the light receiving units may be mounted in a ring or rectangle around a glass fiber, as described below with reference to 9 described.

In integrated photonic systems, the attachment of secondary components, i. H. of light receiving units, also by direct integration. For example, a photodiode can be processed as a light receiving unit directly on, next to or below a planar light guide as a light guide unit in a semiconductor process.

9 shows a schematic representation of a light-guiding device 100 according to an embodiment. Shown is the coupling by means of butt coupling from a light emitting diode as a sending unit 116 in a glass fiber as a light guide unit 102 without medium between sending unit 116 and light guide unit 102 , The non-guided light beams are here by a ring extending around the circular cross section of the glass fiber detector as a light receiving unit 102 added.

10 shows a schematic representation of a beam path through a light guide unit 102 according to an embodiment. In the light guide unit 102 is, for example, a light guide unit, as described above with reference to 2 to 9 is described. This will be light rays 110 with an angle of incidence greater than the acceptance angle of the light guide unit 102 come in, not in the light guide unit 102 guided, but from the core 200 decoupled. If the angles of incidence are smaller than the acceptance angle, then there is total internal reflection and light guidance in the nucleus 200 ,

11 shows a flowchart of a method 1100 for operating a light guide device according to an embodiment. The procedure 1100 For example, in connection with a preceding on the basis of 1 to 10 be described light guide device performed. In one step 1110 an intensity of the component passing by the light-guiding unit and, additionally or alternatively, an intensity of the transmission component received by the jacket of the light-guiding unit by the light-receiving unit are read in. In one step 1120 Furthermore, a measurement signal provided by a measuring unit is received. By way of example, the measuring unit is a measuring cell of an exhaust gas sensor, wherein the light-guiding device is designed to direct the light beam into the measuring cell. Accordingly, the measurement signal may represent a detected by means of the measuring cell exhaust gas concentration. In a further step 1130 A reference intensity is determined using the intensity of the component or the intensity of the transmission component. Finally, in one step 1140 a gas concentration, such as the exhaust gas concentration, determined using the reference intensity and the measurement signal.

In particular, for reference measurements in addition to temporally varying light outputs of the light source, the time-varying transmission, such as at interfaces, an important variable for correct referencing. For example, an optical adhesive, which is introduced between an LED and a light guide, by light irradiation, temperature influence or chemical Reactions with ambient media age and its Change transmission. This change is detected by a measurement of the proportion of light that is not carried in the light guide unit, and can then be compensated with suitable methods.

12 shows a block diagram of a controller 1200 according to an embodiment. The control unit 1200 may be configured to perform a method as previously described 11 is described, perform or control. For this purpose, the control unit 1200 a read-in unit 1210 for reading in an intensity signal representing the intensity of the component or the transmission component 1215 on. A receiving unit 1220 is formed to a provided by the measuring unit measurement signal 1225 to recieve. A discovery unit 1230 is designed to be detected using the intensity signal 1215 a reference intensity 1235 and to a determination unit 1240 forward. The determination unit 1240 is designed to be using the reference intensity 1235 and the measurement signal 1225 a concentration signal representing a gas concentration 1245 provide.

If an exemplary embodiment comprises a "and / or" link between a first feature and a second feature, then this is to be read so that the embodiment according to one embodiment, both the first feature and the second feature and according to another embodiment either only first feature or only the second feature.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited non-patent literature

• M. Hudson, Calculation of the Maximum Optical Coupling Efficiency into Multimode Optical Waveguides, Applied Optics Vol. 5, 1974, pp. 1029-1033 [0056]

Claims (15)

Light guide device ( 100 ) for directing a light beam ( 110 ) to a measuring unit for measuring a concentration of substance or gas, wherein the light-guiding device ( 100 ) has the following features: a light guide unit ( 102 ) with a coupling-in section ( 104 ) for coupling the light beam ( 110 ) and a decoupling section ( 106 ) for decoupling the light beam ( 110 ) in a beam path to the measuring unit; and a light receiving unit ( 108 ), which is designed to prevent one from emitting the light beam ( 110 ) at the light guide unit ( 102 ) passing share ( 112 ) of the light beam ( 110 ) and / or one during the directing of the light beam ( 110 ) between the coupling section ( 104 ) and the decoupling section ( 106 ) decoupled transmission component ( 114 ) of the light beam ( 110 ) to detect and / or forward. Light guide device ( 100 ) according to claim 1, characterized in that the light receiving unit ( 108 ) at the light guide unit ( 102 ) is arranged. Light guide device ( 100 ) according to one of the preceding claims, characterized in that the light receiving unit ( 108 ) adjacent to the coupling section ( 104 ) is arranged. Light guide device ( 100 ) according to one of the preceding claims, characterized by a transmitting unit ( 116 ) for emitting the light beam ( 110 ), the sending unit ( 116 ) the coupling section ( 104 ) and / or the light receiving unit ( 108 ) is arranged opposite one another. Light guide device ( 100 ) according to claim 4, characterized in that the emitting unit ( 116 ) at the coupling-in section ( 104 ) is arranged. Light guide device ( 100 ) according to one of the preceding claims, characterized in that the light-guiding unit ( 102 ) as a light guide with a core ( 200 ) and one the core ( 200 ) surrounding mantle having a smaller refractive index than the core ( 200 ) is realized, wherein the light receiving unit ( 108 ) at least in sections on the jacket ( 202 ) is arranged and adapted to the transmission component ( 114 ) through the jacket ( 202 ). Light guide device ( 100 ) according to one of the preceding claims, characterized in that a subsection ( 500 ) of the light receiving unit ( 108 ) via a coupling section ( 104 ) comprehensive end of the light guide unit ( 102 protrudes). Light guide device ( 100 ) according to one of the preceding claims, characterized in that the light receiving unit ( 108 ) is realized as a photodetector and / or light guide and / or lens. Light guide device ( 100 ) according to one of the preceding claims, characterized in that the light receiving unit ( 108 ) is configured annular or frame-like. Light guide device ( 100 ) according to one of the preceding claims, characterized by a cover element ( 204 ) for opaque covering at least a part of the light receiving unit ( 108 ). Light guide device ( 100 ) according to one of the preceding claims, characterized by at least one further light-guiding unit ( 800 ) with a further coupling-in section for coupling in a further light beam and a further coupling-out section for decoupling the further light beam into a beam path to the measuring unit and / or to a further measuring unit for measuring a substance or gas concentration and at least one further light-receiving unit ( 802 ), which is designed to receive a signal when the further light beam is emitted at the further light-guiding unit ( 800 ) passing portion of the further light beam and / or to detect and / or forward a coupled in guiding the further light beam between the further coupling section and the further decoupling portion transmission portion of the further light beam. Procedure ( 1100 ) for operating a light-conducting device ( 100 ) according to any one of the preceding claims, wherein the method ( 1100 ) includes the following steps: reading in ( 1110 ) an intensity of the at the light guide unit ( 102 ) passing share ( 112 ) and / or an intensity of the transmission component ( 114 ); Receive ( 1120 ) of a measuring signal provided by the measuring unit ( 1225 ); Determine ( 1130 ) a reference intensity ( 1235 ) using the intensity of the light guide unit ( 102 ) passing share ( 112 ) and / or the intensity of the transmission component ( 114 ); and determining ( 1140 ) of a substance or gas concentration using the reference intensity ( 1235 ) and the measuring signal ( 1225 ). Control unit ( 1200 ) with units ( 1210 . 1220 . 1230 . 1240 ), which are adapted to the steps of a method ( 1100 ) according to claim 12 execute and / or to control. Computer program that is adapted to the procedure ( 1100 ) according to claim 12 execute and / or to control. A machine readable storage medium storing the computer program of claim 14.

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