Induction device for measurement light to be spectrally analyzed, manufacturing method of this induction device, and distance and thickness measurement device

Abstract

A guiding device for guiding measurement light to be spectrally analyzed in a distance and / or thickness measurement system, in particular a confocal chromatic aberration type or interferometric distance and / or thickness measurement system, by means of an optical waveguide (11), characterized in that the optical waveguide (11) has an exit end (12) for the measurement light, which is preferably held by a ferrule, and an opening body (1) having an opening (4) is arranged at the exit end (12). Furthermore, a manufacturing method of such a guiding device and a distance and / or thickness measurement device will be described.

Description

Technical Field

[0001] Optical measurement using an optical waveguide in a distance and / or thickness measurement system, in particular a confocal chromatic aberration or interferometric distance and / or thickness measurement system, the optical waveguide having an exit end for measurement light, which is preferably held by a ferrule.

[0002] Furthermore, the invention relates to a distance and / or thickness measuring device, in particular an interferometric and / or confocal chromatic aberration distance and / or thickness measuring device.

[0003] Furthermore, the invention relates to a method for manufacturing an induction device according to the invention.

Background Art

[0004] Both confocal chromatic aberration and interferometric distance and thickness measurement systems are known from the prior art, in which the measurement light to be spectrally analyzed is coupled to a spectrometer by a multimode optical waveguide. The end of the fiber, which is usually circular, also functions as the (point-like) aperture of the light diffusely coupled from the fiber. The spectral image of this fiber end, corrected by a dispersive optical element, finally forms an image on a one-dimensional detector or a multi-dimensional detector. The active surface (pixels) of the detector is usually square and can also be rectangular, especially in the case of a highly sensitive one-dimensional detector. In the case of a rectangle, the height of the individual active cells is greater than the distance between the pixels (also called pixel pitch).

[0005] In such measurement systems, it is always required to simultaneously improve the measurement speed and distance resolution and to measure the distance between two or more layers with high resolution for layer thickness measurement. In addition to using a more sensitive detector that can be read faster, it is important to provide as much measurement light as possible with a good signal-to-noise ratio to improve the speed.

[0006] In order to improve the resolution of the absolute distance of a single measurement object or measurement target layer within a specified measurement range, in a confocal chromatic aberration measurement system, it is sufficient to scan the spectrum to be analyzed with a sensor having a high pixel density. This means that the number of measurement points available for conversion from analog to digital increases, and ultimately, more stable signal analysis and centroid determination become possible. When measuring only one distance, the size of the peak width in the spectrogram relative to the pixel width is not very important. However, when measuring the thickness of a material and it is necessary to resolve the distance between two adjacent reflectors in the spectrogram with sufficient accuracy, in order to ensure that the signals do not overlap as much as possible when the distance is short, in addition to the signal edge being steep, it is necessary to make the width of each measurement peak small relative to the pixel width. The reason is that when the signals overlap, the peaks of the individual signals are added, and ultimately, the individual signals are combined and the analysis thereof cannot be separated.

[0007] In the interference measurement method, the narrower the peak, the higher the modulation degree of the high frequency and the significantly improved distance resolution.

[0008] According to this discovery, in order to improve the resolution of the distance between two adjacent reflectors, it is necessary to reduce the size of the fiber image on the spectrometer column. This can be achieved by using smaller fibers. However, when the spectrum is sharpened in this way, the amount of light that can be captured by the other fiber end on the light source side decreases, so the intensity of the measurement light decreases significantly. ]As a result, the exposure time becomes longer and the measurement frequency decreases.

[0009] Another way to reduce the beam diameter on the row without significantly increasing the optical losses is to simply design the required optical system appropriately and reduce the imaging of the fiber end onto the detector row. However, this option is disadvantageous. The reason is that the requirements for correcting the imaging errors of these optical systems are high, and in particular, when the dispersion is necessarily stronger and the spectral resolution element has a larger field of view angle, the disadvantages clearly outweigh the advantages. These disadvantages include an increase in space requirements and weight due to a more complex optical system, and a significant increase in the manufacturing cost of these optical systems. A seemingly promising solution is to taper the fiber ends terminating in the spectrometer by performing the fiber drawing process under the influence of heat. However, upon closer examination, when the light source is constant, light is transmitted only through a small solid angle from the light source side to the detector surface. As a result, the light spot becomes smaller, but at the same time, only a smaller area of the light source is captured, so its overall intensity decreases. Ultimately, reducing the peak width also results in an unfavorable loss of intensity.

[0010] Furthermore, for illustrative purposes only, refer to Patent Document 1. This Patent Document 1 describes an optical measuring device for measuring the distance and / or thickness of a measurement object. This optical measuring device includes a measurement head having an imaging optical system and an evaluation unit, and the measurement head is connected to the evaluation unit by two optical fiber conductors. The evaluation unit includes a light source, and its light is guided to the measurement head through the first optical fiber conductor. The light reflected from the measurement object is separated into forward light and return light and guided to the second optical fiber conductor by a beam splitter through the measurement head so that the ends of the fibers are in conjugate positions with each other. Furthermore, a separate opening is arranged in front of the end of the optical fiber conductor facing the measurement object. Thus, in order to arrange these openings, extremely accurate arrangement and fixation in three full spatial directions are required. Therefore, the adjustment is very complicated, and the mechanical and thermal stability is reduced by the individual components that need to be connected.

Prior Art Documents

Patent Documents

[0011]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0012] Therefore, an object of the present invention is to design and develop a guiding device that guides measurement light to be spectrally analyzed so that as much measurement light as possible is provided with a good signal-to-noise ratio by using structurally simple means. Furthermore, a manufacturing method of such a device is also specified. Furthermore, an improved distance and / or thickness measuring device for measuring distance and / or thickness is also specified.

Means for Solving the Problems

[0013] According to the present invention, the above object is achieved by the features of claim 1. Therefore, the guiding device of the subject is a guiding device that guides measurement light to be spectrally analyzed in a distance and / or thickness measurement system, particularly in a confocal chromatic aberration type or interferometric distance and / or thickness measurement system, wherein the optical waveguide preferably has an exit end for the measurement light held by a ferrule, and an opening body having an opening is disposed at the exit end.

[0014] And with respect to this guiding device, the above object is achieved by the features of independent claim 13. Independent claim 13 claims a distance and / or thickness measuring device, in particular an interferometric and / or confocal chromatic aberration type distance and / or thickness measuring device, comprising a guiding device for guiding the measuring light as described in any one of claims 1 to 12, and a spectrometer having a detector for evaluating the measuring light, wherein an exit end of the optical waveguide has an aperture body having the aperture and is arranged inside and / or on the spectrometer.

[0015] The distance and / or thickness measuring device according to the present invention results in a significant increase in the light output. This is because the diameter of the optical waveguide, in particular the fiber diameter, becomes significantly larger while maintaining the same spectral selectivity, and the amount of light that can be processed by the measuring system increases significantly. As a result, ultimately, even for materials with low reflectivity, the available measurement frequencies will increase significantly. This is particularly important when used in a device having a rectangular detector array shape with a pixel aspect ratio (PAR) significantly less than 1, and the distance and / or thickness measuring device according to the present invention is advantageous in that it can have such a detector. A further advantage is that a higher selectivity can be achieved compared to a system having an optical waveguide without an aperture. The selectivity of the detector, particularly the spectrometer, refers to the ability to clearly distinguish two adjacent maxima of a continuous spectrum when performing spatially discrete sampling. According to the present invention, due to the lateral action of the aperture, the width of the light source image can be adapted to the aspect ratio of the detector array, so that the selectivity of the spectrometer can be significantly enhanced. In a distance measurement system, increasing the selectivity in a system with the same configuration ultimately means an improvement in the distance resolution. The aperture may be provided directly at the exit end or may be arranged in any manner. Furthermore, not only can the intensity of the light source be changed, but by adjusting the size of the aperture, it is possible to accommodate various light outputs required for specific measurement tasks, so the variable light output is also an advantage. In this case, it is sufficient to use optical waveguides with various aperture shapes.

[0016] Furthermore, the present invention is characterized in that the position of the aperture can be determined particularly easily. The positioning of the aperture with respect to the optical waveguide, particularly the fiber core, can be easily achieved with very high reproducibility by an automated process when the exit end of the optical waveguide or fiber is embedded in the ferrule, and the central position tolerance of the ferrule is preferably less than 1 μm. Furthermore, it is conceivable and advantageous that the exit end of the optical waveguide or fiber has a circular cross-section. A further advantage is that by arranging the aperture at the exit end of the optical waveguide, the optical waveguide is suitable for being arranged in the spectrometer rather than in the measurement head. Such a configuration is realized by the distance and / or thickness measuring device of the present invention. Compared with the case where the aperture is arranged on the measurement head side, this configuration has the further advantage that the aperture does not affect the projection of the measurement light onto the measurement object, but only affects the projection of the light, particularly the spectrally resolved light, onto the detector or detector array. Therefore, only the spectral resolution is improved by the aperture.

[0017] It is advantageous if the aperture is designed as a slit. In other words, the effective aperture has an elongated and narrow shape. And it is even more advantageous if the elongated two side surfaces of the aperture extend at least substantially parallel to each other. Thereby, the image of the optical waveguide can be adapted to the pixel shape of the downstream detector. It is even more advantageous to design the detector in the distance and / or thickness measuring device of the present invention as a one-row detector or a multi-row detector. Such a detector may have square or rectangular pixels with a pixel aspect ratio PAR = xp / yp = pixel width / pixel height in the range from 1 / 40 to 1 / 20. Since the opening is slit-shaped, the active surface of a single-row detector or a multi-row detector can be utilized more effectively.

[0018] It is even more advantageous if the opening has a shape other than rectangular, particularly advantageous if it is in the shape of a futon, a barrel, a lens, or an ellipse. In one embodiment, the opening may be ideally adapted to the detector so as to improve the signal-to-noise ratio. Furthermore, a through-hole-shaped opening may be formed in the opening body. Such a through-hole may be realized as a micro through-hole, and generally has the advantage that it can change the sharpness of the edge of the opening body image on the detector, thereby enabling the shape of the peak tip to be adapted to the requirements of the measurement system. Such an effect can also be achieved by making the opening body partially transparent at least in the edge region of the opening.

[0019] It is advantageous if the opening has an edge that is chamfered in at least some regions. If the material of the opening body has optical gaps or is partially transparent, this can make the edge shape softer when the opening body forms an image on the detector. Thereby, an advantageous effect similar to that of an opening body made of a partially transparent material can be obtained.

[0020] And it is advantageous if this opening body is formed, for example, by a lacquer coating, and this coating is provided at the exit end and is partially transparent or opaque to the measurement light. This enables the opening body to function effectively in a simple way. The coating may be partially removed by microablation, laser ablation, or mechanical means to form the opening. Furthermore, it is also conceivable to print a partially transparent or opaque coating at the outlet end. Therefore, the shape of the opening and, in some cases, other configurations such as through-holes may be pre-created by such printing.

[0021] Also, it is more advantageous if this opening body is formed by a chromium coating printed at the outlet end. A photochemical lacquer may be used on the chromium coating, and this photochemical lacquer is exposed by targeting through a mask corresponding to the opening body or the opening and, in some cases, other configurations, thereby preventing the opening from being etched.

[0022] And it is more advantageous if this opening extends over at least a part of the fiber core of the optical waveguide and also extends over at least a part of the fiber cladding of the optical waveguide.

[0023] It is particularly advantageous if the optical waveguide has a multimode fiber, preferably a graded-index fiber or a step-index fiber. Such fibers are ideal for guiding the light to be spectrally analyzed.

[0024] Also, it is advantageous if the optical waveguide and / or the opening body are aligned such that the measurement light passing through the opening body hits the detector at an angle with respect to the extending direction of the detector pixel. In other words, the image of the outlet end of the optical waveguide may be rotated with respect to the detector pixel to improve the intensity profile detected by the detector pixel. This enables particularly effective imaging onto the detector in the case of special measurement tasks.

[0025] Regarding the method for manufacturing the guiding device, the aforementioned object is achieved by the features of claim 16. That is, claim 16 provides a method for manufacturing a guiding device according to any one of claims 1 to 12, wherein a coating that is partially transparent or opaque is provided at the outlet end of the optical waveguide, and the opening is created by partially removing the coating.

[0026] First, the guiding device according to the present invention may be implemented as a method for manufacturing a guiding device. The corresponding features and related advantages can be clearly made part of the method for manufacturing a guiding device according to the present invention. Furthermore, the features and advantages described with respect to the method for manufacturing a guiding device according to the present invention can also be made part of the guiding device according to the present invention.

[0027] The present invention relates to providing an opening body (especially directly) at the outlet end of a multimode optical waveguide (preferably held by a ferrule), which is (especially grounded). In particular, when the optical waveguide is covered by a ferrule that is accurately centered, the opening body can be provided at the outlet end with high accuracy and high reproducibility. For this purpose, various methods can be used.

[0028] First, it is advantageous to apply a coating that is partially transparent or opaque to the outlet end and then expose the opening using laser ablation. The great advantage here is that since a mask is not required, this procedure can be used very flexibly. Furthermore, in order to affect the reduction in the intensity of the edge region of the opening body or the opening for imaging, the previously applied layer may be gradually removed or made partially transparent by providing minute through-holes.

[0029] It is even more advantageous if the opening body is printed at the outlet end. In particular, when the optical waveguide is covered by a ferrule, extremely accurate positioning can be achieved by printing, and the printing technology can be made into a very flexible process.

[0030] It is even more advantageous to create the aperture body using lithography. In this method, first, a chromium layer is applied to the exit end, and by partially exposing the applied photochemical lacquer through a mask, etching of the opening is prevented. Also in this case, individual aperture shapes can be realized.

[0031] Overall, the following advantages can be achieved by the embodiments of the present invention. <More flexible component selection> As a design challenge for detectors and spectrometers, in this very dynamic market segment, there are few components that conform to standards. For example, in the market, there are few row detectors having the same pixel pitch and the same pixel aspect ratio. As a result, every time a component is discontinued or changed, complex and costly optical design changes are required. Making the aperture shape adaptable by laser ablation processing or the like is very simple, so it is possible to flexibly respond to small-scale changes within a limited range. For example, without fundamentally changing the optical design, columns having optical waveguides of various diameters and various pixel pitches and pixel heights can be very flexibly individually adapted. <Fine adjustment of edge sharpness> Since the aperture body can be directly provided at the exit end of an optical waveguide such as a fiber, first, the shape of the opening can be designed as needed (into an elliptical shape, a rectangular shape, a cushion shape, etc.). Next, for example, in order to reduce the sharpness of the edge of an image, it is possible to change the thickness or microstructure of the applied layer. This has the advantage that the intensity peak of the spectrogram can be made very narrow, but it does not fall into an error situation where the number of samples detected by the detector row is insufficient. A further advantage of providing the aperture body directly is that the aperture at the outlet end (preferably in the form of a slit) can be adjusted (e.g., by rotation) to match the detector array. Such fine adjustment can also affect the sharpness of the edges of the image. <Simple optical design> According to the present invention, it is not necessary to significantly reduce the size of the optical image, thus avoiding a significant increase in cost, space, and weight. Furthermore, since the aperture body can be flexibly designed, the degree of freedom in optical design is increased, and other parameters can be optimized. <Improved flexibility> In particular, since the aperture body can be easily manufactured by laser ablation processing, it is possible to very flexibly meet various requirements of the aperture body, such as the shape of the aperture. For example, when other components of the device are changed, such as in the components of the dispersion system, the aperture body of the optical waveguide or the diameter of the optical waveguide is changed, or on the detector array side, the pixel height or pixel pitch of the detector is changed, adjustment of the aperture body may be required. Similarly, special shapes such as a futon-shaped aperture can also be easily created. <Excellent stability> Regarding long-term stability, it is particularly advantageous to provide an aperture body at the outlet end. This is because, unlike the case where the aperture bodies are individually arranged, changes in force and the influence of temperature do not adversely affect the accurate positioning of the apertures. <No loss in the aperture body> When an aperture body is directly provided at the outlet end, when the coating is sufficiently thin, the available apertures can be utilized to the maximum extent. When the aperture bodies are individually arranged, an air gap may be formed between the fiber end and the aperture body, the outlet angle cannot be increased, and a part of the available apertures cannot be utilized.

[0032] There are various possibilities in designing and developing according to the method of the present invention. In this regard, reference should be made to the drawings on the one hand with reference to the dependent claims and on the other hand to the following description of embodiments of the present invention. In connection with the description of embodiments of the present invention based on the drawings, general preferred embodiments and developments will also be described.

Brief Description of the Drawings

[0033]

Fig. 1

Fig. 2

Fig. 3

Fig. 4

Fig. 5

Fig. 6

Fig. 7

Fig. 8

Fig. 9

Fig. 10

Modes for Carrying Out the Invention

[0034] Figures 1 through 4 show, by way of example, the beam image 8 projected from various types of openings onto the column detector 7 and the intensity profiles 10 received by the column detector 7. For the sake of simplicity, the intensity profiles 10 are shown in a continuous form rather than as a stepped profile for discrete sampling. Figure 1 shows a column detector 7 in which a plurality of elongated detector pixels 9 are arranged upright and side by side. The circular beam pattern 8 occupies substantially the entire height of the column, and the column detector 7 can process the entire projected light. In order to narrow the peak width and bring the image of the optical waveguide 11 closer to the pixel form, the "natural" dot-shaped opening of the optical waveguide 11 is opened by the aperture body 1 added in the present invention. Figure 2 illustrates the function of such an aperture body 1 and the corresponding intensity profile 10. When properly designed, the intensity of the peak maximum, which has an important influence on the exposure time, is not affected by the lateral function of the aperture body 1, and it is also clear that the light loss by the aperture body 1 only affects the intentional narrowing of the base of the peak.

[0035] Figure 1 shows the ideal profile of a gradient-index fiber. The point spread function is similar to a Gaussian distribution and extends over a number of elongated detector pixels 9. This profile is too wide for use in a spectrometer of a confocal chromatic aberration or interferometric distance measuring device. The reason is that when performing two or more adjacent distance measurements, the individual measurement peaks overlap and cannot be separated.

[0036] As shown in Figure 2, when an aperture body 1 having a slit-shaped opening 4 is provided at the exit end 12 of the optical waveguide 11, a very narrow measurement peak that reaches only a very small number of pixel surfaces is generated. However, there are some drawbacks to a beam profile that is too narrow. On the one hand, in order to achieve high-resolution sub-pixels with a confocal measurement method, it is essential to irradiate a plurality of pixels with a sufficient signal-to-noise ratio in order to stably determine the centroid. On the other hand, there are inactive surface areas between the pixels in the columns of the detector that should not be underestimated, which increases the risk of intensity degradation during detection as the signal width decreases. In extreme cases, in the confocal measurement method, this can lead to signal loss, and in the interferometric measurement method, additional vibrations are added to the measurement signal, which may lead to the formation of artifacts.

[0037] Therefore, the ideal width of the aperture 4 depends on the pixel pitch specific to the model of the column detector 7, the ratio of the active surface to the inactive surface, and the specific requirements of the spectral resolution. Due to the width of the aperture 4, the numerical aperture of the optical waveguide 11, and the manufacturing tolerances and adjustment tolerances of the optical system attached to the spectrometer, variations occur in the intensity distribution of the optical waveguide 11 imaged on the detector pixel 9. The aperture body 1 is directly connected to the exit end 12 and is usually embedded in a circular ferrule, so the image of the exit end 12 can be rotated relative to the detector pixel 9, and the intensity profile 10 detected by the detector pixel 9 can be changed (see Fig. 3). By rotating, the base of the peak becomes slightly wider, and the number of pixels required for scanning increases. This makes it possible to more reliably identify the position of the centroid in the confocal measurement method. The rate of increase in the width of the peak in the tip region during rotation is slow compared to the rate of increase in intensity from the non-detection region to the peak.

[0038] Another feasible method to achieve a specific weighting at the tip of the peak while using a sufficient number of pixels to determine the pixel position is to use a partially transparent layer material for the aperture body 1 (see Fig. 4). This creates a prominent bell-shaped pixel width compared to the non-detection region. Since the tip of the peak is narrow, the exact position is maintained. A similar effect can also be achieved by the through-hole-shaped opening 6 of the opening body 1 (for example, using laser ablation processing). With the plurality of manufacturing processes presented in this specification, various opening shapes can be accurately manufactured. Some of them are shown as examples in FIGS. 5 to 9.

[0039] FIG. 5 shows the opening body 1 having an opening 4 designed as a parallel slit and provided at the exit end 12 of the optical waveguide 11. Manufacturing in this way allows not only the fiber core 2 but also the fiber cladding 3 to be exposed by a simple parallel slit. This enables the entire opening to be used in the height direction of the slit.

[0040] FIG. 6 shows the opening body 1 with chamfers 5 provided at the edges of the opening 4. When the material of the opening body 1 has an optical gap, thinning the edges of the gap in this way may make the image of the edges softer. This is similar to the effect shown in FIG. 4. When forming the opening 4 by laser ablation processing, such edges can be formed by a laser beam.

[0041] As an advantageous design of the opening 4, a barrel shape (see FIG. 7) or a zabuton shape (see FIG. 8) can also be adopted. Also, as shown in FIG. 9, by adopting a through-hole-shaped opening 6 or a micro through-hole, the edges of the opening 4 can be sharpened or the optical sealing performance of the opening body 1 can be enhanced.

[0042] FIG. 10 shows an embodiment of a distance and / or thickness measuring device according to the present invention. This device includes, for example, a distance and / or thickness measuring device according to the present invention that introduces measurement light as shown in FIGS. 1 to 9 described above. What is important here is that the exit end 12 of the optical waveguide 11 having the aperture body 1 is arranged inside or on the spectrometer 13. Therefore, the aperture body 1 does not affect the projection of the measurement light onto the object to be measured.

[0043] The function of the distance and / or thickness measuring device is as follows. The illumination light is directed from the light source 14 through a part of the optical waveguide coupler and the lens 15 onto the object to be measured (not shown). The measurement light is coupled from the object to be measured through the lens 15 into the optical waveguide 11 of the optical waveguide coupler. Via the exit end 12 of the optical waveguide 11 arranged inside the spectrometer 13, the measurement light is, in some cases, guided to the detector 16 via further optical elements. The detector 16 is designed as a line detector in this embodiment. In the embodiment shown here, the optical waveguide 11 is part of an optical waveguide coupler, and the optical waveguide coupler is composed of a path from the light source to the coupling point, a path from the coupling point to the lens, and a path from the coupling point to the spectrometer (optical waveguide 11). The coupling point can also be formed by a beam splitter (cube). The path between the coupling point and the lens 15 does not necessarily have to be formed either, that is, the common forward and return paths may be omitted. The optical waveguide 11 of the embodiment shown in this specification may be designed as a fiber fusion or fiber polishing coupler. It should be particularly noted that the beam path of the illumination light and the beam path of the measurement light may be designed to be different. The only important point is that the exit end 12 of the optical waveguide 11 is arranged on the spectrometer side.

[0044] Regarding further advantageous embodiments of the present invention, for the sake of avoiding repetition, reference may be made to the general part of the specification and the appended claims.

[0045] Finally, embodiments of the present invention are for explaining the claimed teachings and are not intended to limit the teachings to the embodiments.

Explanation of Reference Numerals

[0046] 1 ··· Opening body 2 ··· Fiber core 3 ··· Fiber cladding 4 ··· Opening 5 ··· Chamfer 6 ··· Through-hole-shaped opening 7 ··· Row detector 8 ··· Beam pattern 9 ··· Detector pixel 10 ··· Intensity profile 11 ··· Optical waveguide 12 ··· Outlet end 13 ··· Spectrometer 14 ··· Light source 15 ··· Lens 16 ··· Detector

Claims

1. An induction device that guides measurement light to be spectrally analyzed in a distance and / or thickness measurement system, particularly a confocal chromatic aberration type or interference type distance and / or thickness measurement system, by an optical waveguide (11), wherein the optical waveguide (11) has an exit end (12) for the measurement light held by a ferrule, and an aperture body (1) having an opening (4) is arranged at the exit end (12). The induction device is characterized by this.

2. The induction device according to claim 1, wherein the opening (4) is designed as a parallel slit.

3. The induction device according to claim 1 or claim 2, wherein the opening (4) has a shape different from a rectangle, particularly a tatami mat shape, a barrel shape, a lens shape, or an elliptical shape.

4. The induction device according to any one of claims 1 to 3, wherein a through-hole-shaped opening (6) is formed in the aperture body (1).

5. The induction device according to any one of claims 1 to 4, wherein the opening (4) has a chamfered edge in at least a part of the region.

6. The induction device according to any one of claims 1 to 5, wherein the aperture body (1) is partially transparent at least in the edge region of the opening (4).

7. The aperture body (1) is made of lacquer and formed by a coating, and the coating is provided at the exit end (12) and is partially transparent or opaque to the measurement light. The induction device according to any one of claims 1 to 6 is characterized by this.

8. The induction device according to claim 7, wherein the coating is partially removed by microablation processing, laser ablation processing, or mechanical means to form the opening (4).

9. The induction device according to any one of claims 1 to 7, wherein the aperture body (1) is formed by a chromium coating printed at the exit end (12).

10. A partially exposed photochemical lacquer is arranged on the chromium coating, and the opening (4) is formed by etching. The induction device according to claim 9 is characterized by this.

11. The guiding device according to any one of claims 1 to 10, characterized in that the opening (4) extends over at least a part of the fiber core (2) of the optical waveguide (11) and also extends over at least a part of the fiber cladding (3) of the optical waveguide (11).

12. The guiding device according to any one of claims 1 to 11, characterized in that the optical waveguide (11) has a multimode fiber, preferably a graded-index fiber or a step-index fiber.

13. A distance and / or thickness measuring device, in particular an interferometric and / or confocal chromatic aberration type distance and / or thickness measuring device, comprising a guiding device for guiding the measuring light according to any one of claims 1 to 12, and a spectrometer (13) having a detector (16) for evaluating the measuring light, wherein the exit end (12) of the optical waveguide (11) has the opening body (1) having the opening (4) and is arranged in and / or on the spectrometer (13), the distance and / or thickness measuring device.

14. The distance and / or thickness measuring device according to claim 13, characterized in that the detector (16) is designed as a one-row detector (7) or a multi-row detector.

15. The distance and / or thickness measuring device according to any one of claims 1 to 14, characterized in that the optical waveguide (11) and / or the opening body (1) are aligned such that the measuring light passing through the opening body (1) strikes the detector (16) at an angle oblique to the extending direction of the detector pixels (9) of the detector (16).

16. A coating that is partially transparent or opaque to the measuring light is provided at the exit end (12) of the optical waveguide (11), The method for manufacturing the guiding device according to any one of claims 1 to 12, wherein the opening (4) is created by partially removing the coating.

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