CN217739555U

CN217739555U - Holding device for an optical fiber and positioning device having the holding device

Info

Publication number: CN217739555U
Application number: CN202090000459.0U
Authority: CN
Inventors: 阿克塞尔·格拉伯维斯基
Original assignee: Physik Instrumente PI GmbH and Co KG
Current assignee: Physik Instrumente PI GmbH and Co KG
Priority date: 2019-02-06
Filing date: 2020-02-05
Publication date: 2022-11-04
Anticipated expiration: 2030-02-05
Also published as: EP3914946A1; JP3235999U; WO2020160731A1; DE102019102965A1

Abstract

The utility model relates to a holding device (1) for optic fibre, this holding device arranges on positioner (3). The holding device (1) comprises an arm section (4) and a holding section (5), and the proximal end (6) of the arm section (4) is designed to be arranged on the positioning device (3). The holding section (5) is located at the distal end (7) of the arm section (4) for holding the optical fiber (2), and at least two plate-like or disc-like capacitive sensor elements (10) are arranged adjacent to the optical fiber (2) at the arm section (4) for simultaneously determining the distance and position between the optical fiber (2) and an element or structure against which the optical fiber (2) is positionable. The invention also relates to a positioning device (3) having such a holding device (1).

Description

Holding device for an optical fiber and positioning device having the holding device

Technical Field

The present invention relates to a holding device for an optical fiber and a positioning device having such a holding device.

Background

Due to the continuous miniaturization of electronic devices and the desire for higher information transmission speeds, there are many industrial fields that are devoted to transmitting information using light and directly realizing the processing of the light information at the chip level.

In the semiconductor industry, large numbers of Integrated Circuits (ICs) are often manufactured on so-called wafers. A single IC includes a large number of microstructures and nanostructures. In order to couple information from the IC structure directly into the light-guiding element, for example a single optical fiber or a bundle of optical fibers, it is necessary to bring the optical fiber or fibers near the surface of the microstructure in order to read out the information for testing purposes or to bring the optical fiber(s) directly into the correct position in order to connect them in a further process step with the microstructure, for example by means of an adhesive process. The first described test procedure is important in order to find out at an early stage of the semiconductor manufacturing process which of the already manufactured structures are available and which are not. With this knowledge, it is possible to decide which of the structures to further process.

When referring to optical fibers in the following, this does not necessarily mean individual optical fibers, but may also refer to fiber bundles, e.g. arranged in an array. A clear distinction is made only when deemed necessary for an understanding of the corresponding parts of the description. In this application, the optical fiber may be used to couple light emanating therefrom, for example, into an optical element of a substrate or wafer, or light from such an optical element may be coupled, for example, into an optical fiber.

In use it must be possible to move the optical fibre so that it can be brought into an optimum position relative to another element, for example an optical element attached to or integrated into the wafer. For positioning, the optical fiber together with the fiber holder is usually attached at a positioning system which allows moving the optical fiber relative to the optical element. Here, it may be advantageous to move the optical fiber with three translational degrees of freedom and three rotational degrees of freedom. It should be noted that the distance between the front side of the fiber and the wafer surface is typically between 5 μm and 500 μm. In an electronically controlled overlay routine, the optical fiber can be optimally positioned with respect to the surface or with respect to the optical element. "optimal" here primarily refers to the maximum amount of light from the optical elements of the wafer that is coupled into or from the optical fiber into the optical element. During this entire process, it is helpful to know accurately or permanently measure the distance of the fiber relative to the surface or optical element. This can be used in particular as collision protection for optical fibers to exclude contact with the surface of the wafer or optical element.

From US7183759B1 a coupling optics with a distance sensor for positioning an optical fiber array relative to a wafer is known, wherein a plurality of optical fiber arrangements are arranged parallel to each other on a fiber array holder, and a capacitive sensor, which is arranged on the fiber array holder spaced apart from the optical fibers, for determining the distance between the facets of the optical fibers and the optical elements of the wafer.

Only the basic or schematic arrangement of the fiber array and capacitive sensors on the fiber array holder is known from schematic 19 of US7183759B1 and the corresponding part of the description in column 20, lines 37 to 54, but lacks detailed information of a specific design. As shown in fig. 3A to 3C, the applicant believes that the optical fibers of the optical fiber array are arranged in an inclined orientation relative to the optical fiber array holder (i.e., protruding from the plane of the drawing). It is also believed that the capacitive sensor having the structure shown in fig. 1 of the present invention is arranged in an embedded manner in the fiber array holder, and it can be seen that its dimension in the direction parallel to the optical fibers is significantly larger than fig. 19 of US7183759B 1. Under such assumption constraints, the arrangement of the capacitive sensor relative to the optical fiber, i.e. laterally spaced therefrom, is understandable, since when the capacitive sensor is arranged behind the optical fiber (relative to the viewing direction towards the optical fiber or the plane of the drawing), in particular when the capacitive sensor is arranged close to the optical fiber, a collision situation can result between the obliquely extending optical fiber and the upwardly protruding capacitive sensor or its supply line, as shown in fig. 2 of the present invention.

The arrangement between the capacitive sensor and the fibre array shown in figure 19 of US7183759B1 is disadvantageous in that the distances of the individual fibres to the capacitive sensor are significantly different from each other, so that a relatively accurate distance determination is only possible for the fibre closest to the capacitive sensor when the fibre array holder is accidentally tilted about an axis extending perpendicular to the longitudinal extension of the fibre array holder, which distance determination becomes inaccurate as the distance to the capacitive sensor increases relative to the other fibres. In the worst case, there is even contact between the more remote optical fibers and the corresponding optical elements of the wafer during the positioning of the optical fibers.

SUMMERY OF THE UTILITY MODEL

Fig. 3 of the present disclosure uses fig. 3 a) and 3 b) to illustrate a possible source of error in the positioning of a plurality of optical fibers 204 embodied as optical fiber ribbons arranged at a holding device 202 with respect to a wafer 206 arranged on a wafer holder 207 or a surface of the wafer 206 in a corresponding top view of the holding device 202 according to fig. 2. In the best case according to fig. 3 a), the optical fibers 204 are arranged parallel to the surface of the wafer 206, so that the corresponding positioning procedure functions as intended. However, when an undesired tilting of the holding device 202 occurs according to fig. 3 b) (here: a tilt around an axis extending parallel to the main extension direction of the holding means 202), it may happen in the worst case that one of the optical fibers is used for adjustment and that the best coupling is sought for the optical element arranged on the wafer 206, while the other optical fiber of the row or array collides with the surface of the wafer 206.

The object on which the invention is based is therefore to provide a holding device for optical fibers, by means of which the position and position of at least one optical fiber arranged on the holding device relative to another element, in particular an optical element, can be optimally determined or adjusted, in order to, on the one hand, enable light to be introduced into the optical element in an optimized or maximized manner through the optical fiber and, on the other hand, reliably avoid collisions between the optical fiber and the optical element.

Starting from a holding device for at least one optical fiber, the holding device comprises an arm section and a holding section, and the proximal end of the arm section is arranged on the positioning device, and the holding section is located at the distal end of the arm section and at a distance from the proximal end thereof. In an advantageous embodiment, the arm segments have an elongated and preferably straight shape and here extend along the respective main extension direction. The arm section can also be bent one or more times and extend essentially along the main direction of extension. The "direction of extension" is in each case to be understood as the direction having at least one portion pointing from the proximal end to the distal end of the arm segment.

The holding section comprises a holding surface, the surface normal of which has an orientation deviating from the main extension direction of the arm section, and on which holding surface a holding element for mounting the optical fiber in a clamping manner is arranged. In this way, the arrangement or installation of the optical fibers inclined with respect to the main direction of extension of the arm sections can be carried out in a simple manner, so that especially backreflection-free coupling of light through the optical fibers is made possible, for example into the optical element with which the optical fibers are to be positioned opposite.

At least two thin plate-like or disk-like capacitive sensor elements are arranged on the arm section of the holding device at positions adjacent to the optical fibers for simultaneously determining the distance and position between the optical fibers arranged on the holding device and an element, preferably an optical element or structure, to which the optical fibers can be positioned opposite. In this case, the capacitive sensor element may be arranged on a surface of a side of the holding device, which side may be arranged such that it faces the element or the structure, or it may be at least partially inserted or embedded into the arm section relative to this side surface. It is also conceivable to embed the capacitive sensor element completely in the arm section or to arrange the capacitive sensor element flush with the respective side surface.

Due to the flat and compact structure of the capacitive sensor element, which is produced from a plate or disc shape, there are few restrictions with regard to its arrangement on the arm section or relative to the optical fiber. An arrangement is possible in which the capacitive sensors are arranged one after the other in the main extension direction of the arm section and are here arranged, in particular, covered with optical fibers, wherein the capacitive sensor element arranged closest to the optical fibers can be arranged very close to it. Furthermore, due to the flat structure, it is possible to arrange in a relatively simple manner, in particular at the arm section or its side surfaces, a plurality of capacitive sensors which can be turned towards the element or structure located opposite the optical fiber. The compact structure of such capacitive sensor elements is associated with a relatively low dead weight, so that even when a large number of such capacitive sensor elements are used, a holding device with a low overall weight is produced, which allows a high positioning speed or a high positioning dynamics.

It may be advantageous that at least two capacitive sensor elements together form a circular arc shape, and in particular a semi-circular shape, in an adjacent arrangement, the chords of which lie in a plane spanned by the holding surface. Thereby, two capacitive sensor elements can be arranged particularly close to the optical fiber.

It may also be advantageous for the capacitive sensor elements to be arranged adjacent to one another such that their respective shortest distances to the optical fiber arranged on the holding section are identical or substantially identical. This arrangement of the capacitive sensor elements, substantially transverse to the main direction of extension of the arm section, on the one hand succeeds in determining the distance between the optical fiber and the element or structure and, on the other hand, in determining the inclination of the arm section about an axis extending parallel to the main direction of extension of the arm section.

It may also be advantageous for the holding device to comprise two capacitive sensor elements which are arranged one behind the other in the main extension direction of the arm section, so that the distances of the two capacitive sensor elements to the optical fiber arranged at the holding section are different. By such an arrangement of the capacitive sensor element extending substantially parallel to the main extension direction of the arm section, on the one hand, the distance between the optical fiber and the element or structure and, on the other hand, the inclination of the arm section about an axis extending substantially transversely to the main extension direction of the arm section can be successfully determined.

It may also be advantageous if the holding device comprises three capacitive sensor elements, which are arranged on the arm section in such a way that lines connecting the centers of adjacent capacitive sensor elements to one another form a triangle. By arranging the capacitive sensor elements in this way, on the one hand, the distance between the optical fibre and the element or structure can be determined, and on the other hand, the inclination of the arm segment about two axes: 1. around an axis extending substantially transversely to the main extension direction of the arm section onto the holding section; around an axis extending substantially parallel to the main extension direction of the arm section onto the holding section.

It may also be advantageous if the holding device comprises four capacitive sensor elements which are arranged on the arm section in such a way that a line connecting the centers of adjacent capacitive sensor elements to one another forms a square. It is thus possible to use two capacitive sensor elements and thus to measure in pairs for ungrounded counter electrodes, whereby, on the one hand, the distance between the optical fiber and the element or structure can be determined and, on the other hand, the inclination of the arm section about two axes: 1. around an axis extending substantially transversely to the main extension direction of the arm section onto the holding section; around an axis extending substantially parallel to the main extension direction of the arm section onto the holding section.

It may be advantageous if the width or diameter of the capacitive sensor element is at least three times greater than its thickness, so that the capacitive sensor element has a flat or thin shape. It is particularly advantageous here if the width or diameter of the capacitive sensor element is at least ten times greater than its thickness. The capacitive sensor elements thus have a geometry or flatness that is optimized for their arrangement on the arm sections of the holding device, so that the capacitive sensor elements can be arranged or attached at the respective surfaces of the arm sections, if necessary, without their complete or partial embedding therein. This allows a particularly simple type of manufacture of the retaining device, while being compact in size.

Furthermore, it may be advantageous if the distance between the center points of adjacent capacitive sensor elements is less than 10mm. This also contributes to keeping the device very compact in design.

Furthermore, it may be advantageous for the compact structure of the holding device that the distance between the center of each capacitive sensor element and the optical fiber is less than 20mm. This includes that the distance between the centre of the capacitive sensor element, which is the furthest from the optical fibre, and the optical fibre is also less than 20mm.

Furthermore, it may be advantageous for the capacitive sensor element to be inserted into the arm portion such that the capacitive sensor element is flush with a side surface of the holding device. A flush closure with the side surface of the holding device, which faces the component, for example an optical component or a substrate or a wafer, during positioning of the optical fibers, is particularly advantageous. The resulting embedding of the capacitive sensor element into the arm section results in a compact holding device, while protecting the sensor element from mechanical attacks.

The invention also relates to a positioning device with a holding device according to any of the preceding embodiments.

The invention also relates to a method for simultaneously determining distance and position when positioning an optical fiber relative to an element or structure using the above-mentioned holding device, wherein measurement signals obtained by a capacitive sensor element at a single position are used for determining the distance and position between the optical fiber and the element or structure. This means that in the method according to the invention, a plurality of positions are not approached in time in succession, and then the position of the optical fiber or the position of the optical fiber relative to the element or structure is determined from the measurement signals of the capacitive sensor elements of different positions, which makes the method according to the invention very simple and fast.

It may be advantageous here for alternating voltage signals comprising a phase difference of 180 degrees to be applied in pairs to the capacitive sensor elements, and for the elements or structures, against which the optical fibers are positioned, to have an undefined potential.

Drawings

The advantages and utility of the present invention will become more apparent from the following description of the preferred embodiments with reference to the accompanying drawings. In the drawings:

FIG. 1: capacitive sensors according to the prior art;

FIG. 2 is a schematic diagram: holding device for optical fibers according to the prior art;

FIG. 3: illustration for elucidating the measurement problem in the case of a tilted holding device according to fig. 2, wherein an optical fiber array is arranged on the holding device;

FIG. 4: according to the utility model discloses a holding device for optical fiber;

FIG. 5: a positioning system having a positioning device and a holding device according to the invention arranged thereon;

FIG. 6: a diagram for illustrating the measuring principle of a capacitive sensor element using a holding device according to the invention;

fig. 7 a) to 7 c) (not belonging to the present invention): different embodiments of a holding device with a single capacitive sensor;

fig. 8 a) to 8 e): according to a different embodiment of the holding device according to the invention, the holding device has two or three capacitors or sensor elements arranged thereon for determining the distance and position according to a first measurement principle; and

fig. 9 shows an embodiment of a holding device according to the invention with four capacitive sensor elements arranged thereon for determining distances and positions according to a second measurement principle.

Detailed Description

Fig. 1 shows the internal structure of a capacitive distance sensor 102 according to the prior art in a schematic representation. The capacitive distance sensor 102 is implemented in a cylindrical shape and has the outlet cable duct of the cable 101 of the system, which is generally designed as a triaxial cable, designed axially to the rear or in fig. 1 to the top. The use of a triaxial cable is advantageous because the actual sensor signal has to be guided back to the respective electronics using a special type of shielding. The sensor 102 may be used to measure the distance to the surface of an object that acts as a counter electrode 105. The counter electrode must be at a defined potential in relation to the electronics of the sensor.

The sensor 102 has two front sensor surfaces 108 and 110. The sensor surface 110 is used for the actual capacitance measurement, while the second sensor surface 108 is controlled such that the electric field between the sensor 102 and the counter electrode 105 in the inner electrode area is as uniform as possible. The measuring electrode 107 and the guard electrode 103 of the capacitive distance sensor 102 are designed as cylindrical components and are arranged coaxially with respect to one another. The entire system is closed towards the outside by a sensor body or sensor housing 111, which sensor body or sensor housing 111 is normally connected to ground and therefore at GND potential, in order to keep the sensor electrically neutral towards the outside. The individual components are separated from one another by electrically insulating

elements

104 and 109. In the upper region of the sensor, a cavity 112 is provided, which cavity 112 allows the connection of the individual electrodes and the outer electrode to the cable 101. The cable 101 is firmly connected to the sensor housing 111 by means of a connecting element 106 serving as a strain relief.

Fig. 2 shows a holding device for an optical fiber according to the prior art with a capacitive distance sensor according to fig. 1. The holding device 202, which is embodied in the form of a cantilever, is arranged here on a positioning device 201, which is only schematically illustrated in fig. 2, so that the optical fiber 204 can be positioned relative to a wafer 206 arranged at a wafer holder 207. On the inclined front surface of the holding device, a holding element 205 is arranged, which holding element 205 holds the optical fiber 204 in the desired orientation. The orientation is such that back reflection of light into the optical fiber does not occur when light is coupled into the wafer. A capacitive sensor 203 is embedded in the holding device 202 in a spaced-apart manner from the optical fiber 204, the measuring surface of the capacitive sensor 203 being arranged substantially parallel to the plane spanned by the wafer 206.

It is desirable to place the capacitive sensor 203 as close to the optical fiber 204 as possible in order to keep the measurement error associated with the distance measurement between the optical fiber 204 and the wafer 206 as low as possible. However, in the holding device according to the prior art of fig. 2, the closer the capacitive sensor is placed to the optical fiber, the greater the possibility of collision between the capacitive sensor 203 and the optical fiber 204, thereby excluding any arrangement of proximity of the capacitive sensor 203 to the optical fiber 204 without changing the position of the capacitive sensor.

Arranging the capacitive sensor adjacent to the optical fiber such that the capacitive sensor 203 is at substantially the same distance from the positioning device 201 as the optical fiber 204 is at from the positioning device 201, rather than behind the optical fiber as shown in fig. 2, such that the capacitive sensor is at a distance from the positioning device that is smaller than the optical fiber is from the positioning device, is generally not advisable, since it is not usual to use only one such holding device or corresponding positioning system in the arrangement above the wafer, but more than two, whereby light is coupled into the wafer, for example by the optical fiber of the holding device, and light coupled into the wafer is coupled out again by the optical fiber of the other holding device. In order to bring the fibres of the two holding devices as close as possible, the fibres should form the only foremost point, in the ideal case the foremost tip of the holding device.

Fig. 4 shows a holding device 1 according to the invention with an arm section 4, the proximal end 6 of which arm section 4 is arranged on a positioning device 3, which is only schematically shown in fig. 4, to position or align the holding device 1 and thus the optical fiber 2 attached thereto relative to an optical element (not shown in fig. 4) attached to a structure realized as a wafer 8 or integrated therein. The arm segments 4 have an angled shape, however the arm segments 4 extend substantially along a main extension direction HE, or a main part of the arm segments 4 extends parallel to the main extension direction HE, wherein the main extension direction HE extends substantially parallel to the wafer 8 supported by the wafer holder 81 in the arrangement shown in fig. 4.

A holding section 5 with a holding surface 51 is provided on the distal end 7 of the arm section 4, the surface normal of the holding surface 51 having an orientation deviating from the main direction of extension HE, wherein the holding surface 51 thus extends obliquely to the main direction of extension HE. On the holding surface 51, a holding element 55 is provided for holding the optical fiber 2 in a force-fitting manner, preferably in a clamping manner. However, it is also conceivable to retain the optical fiber 2 in the retaining element 55 in other ways, for example by form fit or material fit.

Due to the oblique orientation of the holding surfaces 51 relative to the main direction of extension HE of the arm segments 4 and the corresponding design of the holding elements 55, the optical fibers 2 held by the holding elements 55 are also oriented obliquely relative to the main direction of extension HE of the arm segments 4, so that an orientation of the optical fibers 2 relative to the wafer results which deviates from a right-angled orientation. In this way it is ensured that the light can be guided without or substantially without back reflection through the optical fiber 2 into the optical element arranged on or integrated in the wafer 8.

On a side surface 9 of the holding device 1 facing the wafer 8 or an optical element arranged thereon or integrated therein and in the immediate vicinity of the optical fiber 2, at least two plate-like or disk-like capacitive sensor elements 10 for simultaneously determining the distance and position between the optical fiber 2 and the optical element or the wafer 8 are provided, wherein only one of the capacitive sensor elements 10 arranged one behind the other in the viewing direction can be seen in fig. 4. The capacitive sensor element 10 is partially inserted or embedded in the arm section 4. However, it is also conceivable for the capacitive sensor elements 10 to be completely embedded in the arm section 4 or to be embedded therein and for their surface to be flush with the side surface 9. It is also conceivable that the capacitive sensor element 10 is not embedded or inserted at all into the arm section 4, but is arranged on the surface of the side surface 9 and preferably glued thereto.

Fig. 5 shows a positioning system 60 with a holding device 1 according to fig. 4, a positioning device 3 and a corresponding electronics unit 50, which electronics unit 50 is connected to the optical fiber 2, the two capacitive sensor elements 10 and the positioning device 3. By means of the connection between the optical fiber 2 and the electronic unit 50 it is possible to either couple light into the optical fiber 2 or measure the amount of light coupled into the optical fiber 2.

The two capacitive sensor elements 10 (only one of which is visible in fig. 5) are each connected to the electronics unit 50 by means of a cable 101, so that the measured values generated by the capacitive sensor elements 10 can be read by the electronics unit 50 and information about the distance of the holding device 1 from the wafer 8 and about the position of the front portion of the optical fiber 2 relative to the surface of the wafer 8 can thus be obtained.

Furthermore, the positioning device 3 is connected to the electronic unit 50 via a cable 301, wherein the data measured by the two capacitive sensor elements 10 are used to control or adjust the positioning device 3 accordingly in order to adjust the position of the optical fiber 2 with respect to the surface of the wafer 8 or with respect to an optical element arranged thereon or integrated therein with at least two degrees of freedom and at most six degrees of freedom. The electronic unit 50 can here be directed, for example, in such a way that the distance of the optical fibers with respect to the surface of the wafer 8 is always kept at a constant distance. A search algorithm can then be initiated, for example, by changing the position of the optical fiber relative to the wafer surface or an optical element disposed thereon or integrated therein, such that light coupled into the optical fiber is detected and coupling efficiency is maximized. The position of the optical fiber is thus positioned in a defined optimal position, which is kept at a constant distance from the surface of the wafer 8.

The positioning device 3 is connected in a mechanically rigid manner to the wafer holder 81 and thus to the wafer 8 by means of the connecting element 30.

The positioning device 3 has a drive system which is formed by an electromechanical and in particular piezoelectric drive. However, drive systems with electromagnetic drives or combinations of different drive systems are also conceivable. The positioning device 3 comprises a parallel kinematic device in the form of a hexapod, i.e. a platform moving with respect to a base, wherein the platform is coupled to the base by six legs of variable length. By driving the six legs, either directly or indirectly, the desired attitude of the platform in space and hence the desired orientation and position of the optical fiber 2 relative to the wafer 8 can be set. Alternatively, positioning devices based on a tandem motion system are also possible. To improve the positioning accuracy, it is also conceivable to operate a parallel or series kinematic system in combination with a piezoelectric drive.

Instead of the positioning system 60 shown in fig. 5 having only one positioning device 3, it is also conceivable to provide two positioning devices 3 for independent positioning of two optical fibers 2. This arrangement is used, for example, when one of the optical fibers is used to couple light into the wafer and another of the optical fibers is used to couple light out of the wafer. Here, two optical fibers need to be separated from each other and placed precisely opposite the wafer. As an alternative to this, it is conceivable that the second positioning means position the electronic probe tip relative to the wafer in order to simultaneously couple or out couple the electronic signal and the optical signal, for example by means of the electronic probe tip through an optical fiber.

The capacitive sensor element 10 can be used not only for continuous distance measurement (i.e. to keep the position of the optical fiber constant with respect to the wafer or its surface), but also for preventing the optical fiber 2 from colliding with the surface of the wafer. For this purpose, the electronic unit 50 may be configured such that the positioning device is stopped below a minimum distance of the optical fiber relative to the surface of the wafer, or a warning is output.

Fig. 6 shows a schematic diagram for elucidating the measuring principle using two capacitive sensor elements 10. Here, the surface of the wafer 8, which is measured as a counter electrode, has no defined potential reference with respect to the electronics 70 of the capacitive sensor system. Distance measurement by means of capacitive sensors generally requires a counter electrode with a defined potential. When this is not the case, capacitive distance measurement often fails. The measurement of the capacitance is in most cases carried out as an AC measurement, which means that an alternating measurement signal is coupled into the measurement capacitor and the capacitance between the measurement capacitor and the counter electrode is measured.

In the measurement principle shown in fig. 6, the

plate capacitors

120 and 130 formed between the capacitive sensor element 10 and the counter electrode no longer have a zero potential point. However, to generate an alternative potential path, two capacitive sensor elements with coupled currents can be used. Two capacitive sensor elements 10 are mechanically attached adjacent to each other and controlled with a phase difference of 180 ° in AC control. Thereby generating two

current paths

140 and 150, such that a current displacement between the two capacitive sensor elements 10 occurs. Thus, a capacitance measurement can be made without having to rely on the counter electrode being at a defined potential. To measure the distance, the two distance signals of the respective sensors are subtracted to reduce the noise component. The result is a distance 160 of the center point between two adjacent capacitive sensor elements 10 from the surface of the counter electrode or wafer 8.

Fig. 7 in fig. 7 a) to 7 c) shows three different embodiments of a holding device 1, which do not belong to the invention, the holding device 1 having a single capacitive sensor element 10 arranged thereon or inserted therein. Fig. 7 a) to 7 c) each show the holding device 1 in a viewing direction towards the side surface 9. The optical fibers 2 are held by the holding element 55 and are thus arranged in a defined arrangement at the holding device 1. It can be seen here that the optical fiber 2 represents the foremost point of the holding device 1, whereby it is possible, for example, to position two optical fibers very closely to one another, each of which is arranged on its own such holding device 1.

According to fig. 7 a), the capacitive sensor element 10 is implemented as a single circular sensor element comprising a sensor electrode surface 115 and a guard electrode surface 116. However, other geometries of the capacitive sensor element are also conceivable, for example a rectangular shape according to fig. 7 b). In order to be able to measure closer to the optical fiber, it is also conceivable that the sensor electrode surface 115 and the guard electrode surface 116 of the capacitive sensor element 10 can be realized in the form of a semicircle, as shown in fig. 7 c). It is thereby simultaneously achieved that the distance of the holding device and the distance of the optical fiber to the surface can be measured as closely as possible to the position of the optical fiber, and that the sensor can be positioned behind the optical fiber 2 in the direction of the proximal end 6 in the main direction of extension HE of the holding device.

Fig. 8 shows five different embodiments of a holding device 1 according to the invention in fig. 8 a) to 8 e), wherein in fig. 8 a) to 8 c) a holding device is shown in each case, which has two capacitive sensor elements 10 arranged thereon, while in fig. 8 d) and 8 e) the holding device shown in each case comprises a total of three capacitive sensor elements 10. With the arrangement of the capacitive sensor elements according to fig. 8 a) to 8 e), it is provided that each capacitive sensor element 10 itself measures a counter electrode with a defined potential individually.

According to fig. 8 a), two capacitive sensor elements 10 are arranged on the side surface 9 of the arm section 4 in the region of the holding section 7. The capacitive sensor element 10 is arranged here to be at least partially embedded in the arm section 4 or embedded in the arm section 4. The two capacitive sensor elements 10 each have a sensor electrode surface 115 and a guard electrode surface 116 and are embodied in the form of a quarter circle. As a result of the capacitive sensor elements 10 being embodied adjacent and symmetrically arranged with respect to the main direction of extension HE of the arm section 4, these capacitive sensor elements 10 together form a semicircle whose chord lies in the plane spanned by the holding surface 51. The holding element 55 is also embodied in the form of a semicircle or a semicircular disk and bears with its flat side or surface against the holding surface 51. In the center of the holding element 55, an opening is provided through which the optical fiber 2 protrudes, the optical fiber 2 being arranged at the arm section 4 or its holding section 7 by means of the holding element 55.

The four-part circular shape of the two capacitive sensor elements 10 and the arrangement in which they are formed as a semi-circle, with the circular chord of the semi-circle coinciding with the plane spanned by the holding surface 51, allow the capacitive sensor elements 10 to be placed at the optical fiber 2 as quickly as possible. Due to the corresponding design of the holding element 55, the optical fiber 2 is moved closer in particular to the two capacitive sensor elements 10.

Fig. 8 b) shows a further embodiment possibility of the holding device according to the invention, wherein two capacitive sensor elements 10 each having a sensor electrode surface 115 and a guard electrode surface 116 have a circular shape and are arranged in an adjacent arrangement in the region of the holding section 7 at the side surface 9, so that the two capacitive sensor elements 10 are partially inserted or embedded in the arm section 4. An imaginary line connecting the center points of the two circular capacitive sensor elements 10 to each other extends substantially transversely to the main direction of extension HE of the arm section 4. Due to this arrangement the centre points of the capacitive sensor elements have substantially the same distance to the optical fibre 2. The holding element 55 has a web section and a circular section with a central opening through which the optical fiber 2 protrudes.

The embodiment of the holding device according to the invention according to fig. 8 c) differs from the embodiment according to fig. 8 b) only in that two circular capacitive sensor elements 10 are arranged in series along the main direction of extension HE, so that the center points of the capacitive sensor elements have different distances to the optical fiber 2.

In an embodiment of the holding device according to the invention according to fig. 8 d), the holding device has a total of three capacitive sensor elements 10, which three capacitive sensor elements 10 are arranged symmetrically with respect to the main direction of extension HE at the side surface 9 of the arm section 4. Here, the capacitive sensor element is partially inserted or embedded in the arm section 4. Three imaginary lines each connecting the center points of two adjacent capacitive sensor elements 10 together form a triangle. Fig. 8 e) shows another possible arrangement when three capacitive sensor elements 10 are used, wherein two capacitive sensor elements 10 arranged closer to the optical fiber 2 are arranged symmetrically with respect to the main direction of extension HE, while a third capacitive sensor element 10 is arranged behind one of the two aforementioned capacitive sensor elements 10 in a direction parallel to the main direction of extension HE.

Fig. 9 shows a further embodiment of a holding device 1 according to the invention with four capacitive sensor elements, wherein every two capacitive sensor elements are measured together in pairs against a counter electrode without a defined potential. The four capacitive sensor elements 10 are arranged here symmetrically in pairs with respect to the main direction of extension HE. The four capacitive sensor elements 10 are arranged with respect to one another such that lines connecting the center points of immediately adjacent capacitive sensor elements to one another together form a quadrilateral.

It goes without saying that the capacitive sensor elements 10 shown in fig. 8 a) to 8 e) and in fig. 9 can have other geometric shapes, for example the square shape shown in fig. 7 b).

Description of the reference numerals:

1. holding device

2. Optical fiber

3. Positioning device

4 (of the holding device 1) arm sections

5 holding section (of holding device 1)

6 (of the arm segment 4) proximal end

7 (of the arm segment 4)

8. Wafer with a plurality of chips

9 (of the arm section 4) side surfaces

10. Capacitive sensor element

30. Connecting element

50. Electronic unit

51 Holding surface (of arm segment 4)

55. Holding element

60. Positioning system

70. Electronic device

81. Wafer holder

101. Cable (for electrically connecting the capacitive sensor element 10 to the electronic unit 50)

102. Capacitive distance sensor

103. Protective electrode

104. Insulating element

105. Counter electrode

106. Connecting element

107. Measuring electrode

108. Sensor surface

109. Insulating element

110. Sensor surface

111. Sensor shell

112. Hollow cavity

115. Sensor electrode surface

116. Protecting the electrode surface

120. Flat capacitor

130. Flat capacitor

140. Current path

150. Current path

160 Distance (of center points between two capacitive sensor elements and surfaces of counter electrodes)

201. Positioning device

202. Holding device

203. Capacitive sensor

204. Optical fiber

205. Retaining element

206. Wafer with a plurality of chips

207. Wafer holder

301. A cable (for electrically connecting the positioning device with the electronic unit).

Claims

1. A holding device (1) for at least one optical fiber (2) arranged on a positioning device (3), characterized in that the holding device (1) comprises an arm section (4) and a holding section (5), and wherein a proximal end (6) of the arm section (4) is designed for arrangement on the positioning device (3), and wherein the holding section (5) is located at a distal end (7) of the arm section (4) for holding the optical fiber (2), wherein the arm section (4) extends at least in sections along a main extension direction (HE), and the holding section (5) has a holding surface (51), a surface normal of which holding surface (51) has an orientation deviating from the main extension direction (HE), and wherein two plate-like or disc-like capacitive sensor elements (10) are arranged on the arm section (4) adjacent to the optical fiber (2) for simultaneously determining a distance and a position between the optical fiber (2) and an element or structure relative to which the optical fiber (2) can be positioned.

2. The holding device (1) according to claim 1, characterized in that the at least two capacitive sensor elements (10) are arranged adjacently together forming a circular arc shape with a circular chord lying in a plane spanned by the holding surface (51).

3. The holding device (1) according to claim 1, characterized in that the at least two capacitive sensor elements (10) are arranged adjacently together forming a semicircular shape.

4. The holding device (1) according to any one of claims 1 to 3, characterized in that the capacitive sensor elements (10) are arranged side by side such that their shortest distance to the optical fiber (2) arranged on the holding section (5) is the same.

5. The holding device (1) according to claim 1, characterized in that it has two capacitive sensor elements (10), which two capacitive sensor elements (10) are arranged in series along the main direction of extension (HE) of the arm section (4) such that their respective distances to the optical fiber (2) arranged on the holding section (5) differ from one another.

6. The holding device (1) according to claim 1, characterized in that it has three capacitive sensor elements (10), the three capacitive sensor elements (10) being arranged on the arm section (4) such that lines connecting the centers of adjacent capacitive sensor elements (10) together form a triangle.

7. The holding device (1) according to claim 1, characterized in that it has four of the capacitive sensor elements (10), the four capacitive sensor elements (10) being arranged on the arm section (4) such that a line connecting the centers of the capacitive sensor elements (10) together forms a quadrilateral with respect to the directly adjacent capacitive sensor elements (10).

8. The holding device (1) according to any one of claims 1 to 3, wherein the width or diameter of the capacitive sensor element (10) is at least three times greater than its thickness.

9. Holding device (1) according to any one of claims 1 to 3, characterized in that the distance between the centers of the adjacent capacitive sensor elements (10) is less than 10mm.

10. The holding device (1) according to any one of claims 1 to 3, characterized in that the center of each capacitive sensor element (10) is at a distance of less than 20mm from the optical fiber (2).

11. The holder (1) according to any one of claims 1 to 3, characterized in that the capacitive sensor element (10) is inserted into the arm section (4) such that the capacitive sensor element (10) is flush with a side surface (9) of the holder (1).

12. A positioning device (3), characterized in that the positioning device (3) has a holding device (1) according to any one of claims 1-3.